The Mediterranean ecosystem is suffering the equivalent of a marine wildfire as temperatures in the area are more than 6°C warmer than normal. It is feared that the area is being permanently altered by global heating, with cooler deep water no longer rising to the surface. One study found that these marine heatwaves have already destroyed almost 90% of coral populations around parts of the Mediterranean. This decline has knock-on impacts on biodiversity within the marine ecosystems of the area.
A new project is looking at the genetic differences between bee species. ‘Beenome100’ will look to answer questions on which genetic differences make some species more vulnerable to climate change or more susceptible to different pesticides. By creating a digital repository of the complete set of genes present in 100 US bee species, scientists can link specific genes to bee functions.
Between 1986 and 2020, invasive herpetofauna cost the world $17 billion, $16.3 billion of which were associated mainly with just two species, the brown tree snake (Boiga irregularis) and the American bullfrog (Lithobates catesbeianus). This cost mainly comes from ruined farm crops and triggered power outages. The study’s researchers are hoping that their findings will encourage investment in preventing the spread of invasive species in the future.
Scientists have recorded more than 30 potentially new species from the abyssal plains of the central Pacific. Researchers from the Natural History Museum used a remote-operated vehicle to reach depths of between 3,095 and 4,125 metres and collect over 55 specimens. These specimens include segmented worms and coral, as well as species from the same families as centipedes and jellyfish. The study highlights the potential implications of deep-sea mining for biodiversity.
Conservation
UK wild salmon stocks are reaching a crisis point, with the lowest number on record in England. A government report urges action to remove barriers in waterways and improve water quality. 42 rivers in England are considered ‘salmon rivers’ as they are traditional breeding grounds for the fish. Of these, 37 have been classified as at risk or probably at risk. Warming sea temperatures due to climate change are being blamed, along with poor water quality in rivers and estuaries, with every waterway in England failing pollution tests in 2020. The main sources of pollution are thought to be sewage outflows and agricultural runoff.
Water voles have been reintroduced to the River Beane in Hertfordshire after being locally extinct for more than 20 years. Threatened by habitat loss and predation by the invasive American mink, the species has seen a 90% drop in population over the last five decades. Herts and Middlesex Wildlife Trust, in partnership with the Woodhall Estate and with the support of the River Beane Restoration Association, reintroduced 138 water voles to the river near Watton-at-Stone. Herts and Middlesex Wildlife Trust aim to reintroduce water voles to all Hertfordshire rivers by 2030, through these reintroduction programmes and by improving habitats.
A new Antarctic study has shown that the levels of ‘forever chemicals’ that are reaching this remote continent have been increasing. These chemicals include perfluorocarboxylic acid (PFCAs) and are termed forever chemicals as they do not break down naturally in the environment. They’re used in a variety of ways, such as in non-stick coating for pans and as water-repellents for clothing. The ice cores taken provide a record between 1957 and 2017 and show evidence that levels of these chemicals in Antarctic snow have increased over the last few decades, particularly between 2000 and 2017. There is ongoing research, however, into the clean-up of these forever chemicals, including a new study into bioremediation using a plant-derived material to absorb PFAs, disposing of them by allowing microbial fungi to eat them.
Deforestation
A new study has found that over 60% of global forest area has been lost. Using a global land use dataset, the team of researchers found that global forest area declined by 81.7 million hectares (ha) between 1960 and 2019. Gross forest loss was 437.3 million ha, outweighing gross forest gain during this time, which was 355.6 million ha. The loss of forests, both in the net area and through replacement by new growth/plantations, has a significant impact on the integrity of forest ecosystems, reducing their ability to sustain biodiversity.
In the lead up to the 26th UN Climate Change Conference of the Parties (COP26) in November of last year, and in the months that have followed, we have been writing a series of articles looking at some of the toughest global climate crisis challenges that we are currently facing. This blog looks at the causes of ocean warming and its impacts on marine ecosystems.
Dead coral at Lisianski overgrown with algae after a coral bleaching event in 2015. Image by John Burns via Flickr.
What causes ocean warming?
The ocean acts as a heat sink, absorbing large amounts of heat from our atmosphere and storing it over long periods; the ocean has a central role in stabilising our climate system. This heat is moved and mixed by tides, currents and wave action, allowing the ocean to soak up large amounts of heat without significant increases in temperature. This is changing, however, due to increasing concentrations of atmospheric greenhouse gases. IPCC data published in 2013 suggested that the ocean has absorbed over 90% of the excess heat generated by greenhouse gas emissions since the 1970s. This is resulting in increased ocean temperatures, with the greatest warming occurring in the southern hemisphere and in the upper 75m of the oceans surface. Average global ocean surface temperatures increased by 0.11°C per decade from 1971 to 2010. This heat sink process has helped limit the rise of global average temperatures but it has serious environmental consequences.
What are the impacts of ocean warming?
Ocean warming has a wide range of impacts on ocean chemistry, habitats, ecosystems and biodiversity, the severity and type of which can vary between habitats depending on their resilience and present biodiversity levels. Combined with other stressors such as pollution, acidification and increased nutrient input, ocean warming can increase the vulnerability of habitats and marine life to other threats such as parasites and disease outbreaks.
Water temperature is a significant environmental stressor, particularly in shallow or nearshore habitats, as they often act as nursery areas for many species. If water temperatures within nursery habitats rise above tolerable levels, they will no longer be suitable, impacting the survivorship, growth and recruitment of the species that use them.
Fishing net tangled on a reef. Image by Tim Sheerman-Chase via Flickr
Deoxygenation
Oxygen solubility varies depending on the temperature of the water; warmer ocean water holds less oxygen compared to colder water. Warmer water is also less dense, and rising ocean temperatures leads to increasing ocean stratification, where water is separated into layers. This can act like a barrier and prevents the mixing of water, slowing down ocean circulation and reducing the amount of oxygen reaching deeper waters. It is thought that dissolved oxygen levels have fallen by 2% since the 1950s due to the combined threats of ocean warming and excessive algae growth caused by anthropogenic nutrient input. Areas of low oxygen concentrations have expanded worldwide, with hundreds of new sites reported to be affected and anoxic ocean waters quadrupling in volume since the 1960s.
Ocean deoxygenation has serious consequences for marine ecosystems and biodiversity, as oxygen is necessary to sustain life for almost all organisms in the ocean. Deoxygenation could lead to a decline in species numbers, diversity and individual growth, resulting in major ramifications throughout the food chain. In ecosystems already vulnerable due to other pressures such as overfishing, deoxygenation could lead to extinctions and even deadzones. Hundreds of millions of people rely on the oceans as a source of food and livelihood; they could be severely affected by a reduction or collapse in fish stocks.
Warmer waters also increase the oxygen requirement of fish, exacerbating the effects of deoxygenation. There will likely be a shift in the structure of marine ecosystems as more hypoxia-tolerant species, such as jellyfish, will be favoured over less tolerant species, such as large fish and marine mammals.
Coral bleaching
Corals are marine invertebrates that often have a hard calcium carbonate skeleton. They live in a mutualistic symbiotic relationship with photosynthetic unicellular dinoflagellates called zooxanthellae (endosymbionts), which live in their tissues. They rely on these endosymbionts for up to 95% of their energy requirements. Under certain physiological stresses, such as increasing water temperatures, these endosymbionts can be expelled and the corals turn white without the pigment from the zooxanthellae – this phenomenon is known as ‘coral bleaching’. If the stress continues over an extended period and the coral is not recolonised, the coral will eventually die. Increasing ocean temperatures over the last few decades have resulted in large-scale loss of coral across the world. This has led to degraded coral reef habitats, impacting the ecosystem and species that rely on them. Coral reefs provide food, shelter and spawning grounds for thousands of marine species, therefore the degradation of coral reefs has wide-reaching consequences.
Bent sea rod bleaching. Image by Kelsey Roberts, U.S. Geological Survey via Flickr
Habitat loss and range shifting
All species have a thermal tolerance range. Some more generalist species are able to tolerate a broader range, but specialist species occupy a much narrower thermal niche and are therefore more vulnerable to temperature change. Temperature changes can trigger a knock-on effect on ecosystem structures as species migrate into more suitable habitats. The general trends in these shifts are a movement to higher latitudes and deeper locations.
Many factors affect a species’ capacity to adapt to rising temperatures, including their dispersal ability, thermal tolerances, habitat or resource needs and the community composition of the new potential habitat. If the new area has high levels of pressure from competition, predation or lack of resources, or the species’ dispersal ability is limited (e.g. the species is sessile), successful establishment is unlikely.
Commercial fishing boat. Image by Gary Leavens via Flickr
Changes in community structure can negatively impact biodiversity, as the loss of whole populations from initial habitats can trigger a cascade of consequences on predator and prey populations, potentially altering entire ecosystems. These range shifts can also impact the communities already present, as new species could lead to increased competition for resources or the arrival of a novel predator that prey species are not adapted to avoid. There will also likely be socio-economic impacts on local fisheries if species move away from traditional fishing grounds.
Range shifting has been recorded in zooplankton, where warm-water species are extending their ranges poleward at a rate of up to to more than 230km per decade. There has also been a corresponding decline in the abundance of cold-water species in these areas. Zooplankton play a key role in many food chains as they are an intermediary species, transporting energy from the primary producers (phytoplankton) they consume to their predators, such as fish and decapods. Therefore, these changes in zooplankton community composition impact whole marine food webs, especially as warm-water species are generally smaller and less energy-rich.
Radiolarian zooplankton stack images, composed of dozens of single photographs taken using a microscope at different focus levels. Images 1, 2, and 3 by Picturepest via Flickr.
Temperature-dependent sex determination
Some marine species exhibit environmental sex determination, where certain environmental factors can influence the sex of offspring during embryonic or early juvenile development. With increasing ocean temperatures, the proportion of males to females being born could be altered in certain species, leading to biased sex ratios. This can affect reproduction, genetic diversity and potentially population numbers.
Many fisheries are female-dependant, as female fish tend to grow larger, therefore are more likely to grow to harvestable sizes and can produce a larger yield. Southern flounder (Paralichthys lethostigma) exhibits sex reversal to males during early juvenile development at both 18°C and 28°C, with the optimal temperature for female development being 23°C. Southern habitats consistently have higher temperatures of over 27°C, therefore producing more male-biased sex ratios, potentially impacting the viability of fisheries operating out of these locations.
Other impacts
Warming ocean temperatures are also thought to be impacting breeding patterns, with many species reproducing earlier. This could lead to an uncoupling of certain predator and prey interactions if migrating predators arrive too late to feed during spawning events. Some species have been found to breed for a shorter duration, such as black sea bass (Centropristis striata) whose spawning season is starting later and ending earlier in the northern parts of their range. This suggests that there may be lower reproduction and recruitment in newly occupied ranges, demonstrating the potential future impact of warming ocean waters on species experiencing poleward-driven range shifts. Migration patterns have also been noted to be affected, with similar potential results.
Ocean warming also reduces the amount of sea ice. The implications of this, such as sea-level rise, coastal flooding and erosion, will be covered in more depth in a future blog post.
Coral spawning. Images 1 and 2 by Pei Yan via Flickr
What can be done?
As the main driver for increasing ocean temperatures is the increase in atmospheric greenhouse gases, particularly carbon dioxide, the solution is to reduce our greenhouse gas emissions. Beyond this, we need to protect and restore our marine and coastal ecosystems and manage the other stressors that are exacerbating the impacts of ocean warming. By creating protected areas and restoring degraded habitats, we can create refuges for species and improve biodiversity, which has been shown to increase ecosystem resilience against the impacts of climate change.
By working with fisheries, governments could introduce further policies that work towards sustainability, such as by improving quota limits and reducing by-catch. Many governments and fisheries are already working towards this, but scientific research and accurate data are needed to ensure that population estimates are accurate to prevent overfishing. Steps like these will help to reduce the pressures we place on the marine realm, allowing ecosystems to be more resilient to the effects of ocean warming.
Scientific research into monitoring ocean warming is also important. Up-to-date and accurate measurements, with local and global monitoring of the rates, trends and effects can help policymakers make rapid and correct decisions to mitigate the worst impacts. Many of the policies signed at COP26 may make a positive difference, as reducing deforestation and methane emissions and adopting policies to reach net zero by 2050 will help to limit ocean warming. However, more can and should be done.
Summary
Oceans absorb atmospheric heat, the amount of which has increased due to high greenhouse gas emissions. The greatest warming occurs in the southern hemisphere and the upper 75m.
Ocean warming has a variety of impacts including deoxygenation, habitat loss, range shifting, coral bleaching and changes to breeding patterns. These various impacts can all have negative effects on marine biodiversity and human livelihoods.
As the main driver for marine warming is increased greenhouse gas emissions, the main solution is cutting these emissions. Other solutions include protecting and restoring marine habitats, reducing pressures from other threats such as overfishing and increasing the accuracy and use of scientific research.
This book discusses the modifications in marine ecosystems related to global climate changes, including shifts in temperature, circulation, stratification, nutrient input, oxygen concentration and ocean acidification, all of which have significant biological effects.
Charles Clover chronicles how determined individuals are proving that the crisis in our oceans can be reversed, with benefits for both local communities and entire ecosystems. Essential and revelatory, Rewilding the Sea propels us to rethink our relationship with nature and reveals that saving our oceans is easier than we think.
This authoritative and accessible textbook advances a framework based on interactions among four major features of marine ecosystems – geomorphology, the abiotic environment, biodiversity, and biogeochemistry – and shows how life is a driver of environmental conditions and dynamics.
This special report is the most comprehensive and up-to-date assessment of the observed and projected changes to the ocean and cryosphere and their associated impacts and risks.
This offers a short, self-contained introduction to this subject, beginning by briefly describing the world’s climate system and ocean circulation and going on to explain the important ways that the oceans influence climate. Topics covered include the oceans’ effects on the seasons, heat transport between equator and pole, climate variability, and global warming.
Wally Broecker is one of the world’s leading authorities on abrupt global climate change. In The Great OceanConveyor, he introduces readers to the science of abrupt climate change while providing a vivid, firsthand account of the field’s history and development. This book opens a tantalizing window into how Earth science is practised.
We have recently received the sad news of the passing of James Lovelock, an environmentalist, chemist, futurist and the creator of the Gaia hypothesis.
Born in 1919, he attended the University of Manchester at age 21 and graduated with a PhD from the London School of Hygiene and Tropical Medicine in 1948, becoming an independent scientist in 1961. He had since been awarded honorary degrees from several institutions, including the University of Exeter, Stockholm University and the University of Colorado Boulder. His career was varied, from travelling aboard the research vessel RRS Shackleton to working on developing scientific instruments for NASA, and even performing cryopreservation experiments.
Lovelock was the first person to detect Chlorofluorocarbons (CFCs) in the atmosphere after developing an electron capture detector in the late 1960s. CFCs are nontoxic chemicals used in the manufacturing of products such as aerosol sprays, and are used as solvents and refrigerants. Their role in the depletion of the ozone layer led to their inclusion in the Montreal Protocol, which worked to phase out several substances to protect the ozone layer. During his time aboard the RRS Shackleton, Lovelock measured the concentration of CFC-11 from the northern hemisphere to the Antarctic. These experiments provided the first useful data on the widespread presence of CFCs in the atmosphere, though the damage these cause was not discovered until the 1970s, by Sherwood Rowland and Mario Molina.
James Lovelock was also known for his Gaia hypothesis. This hypothesis, first created in the 1960s, proposed that the complex interacting system of the Earth’s biotic and abiotic parts could be considered as a single organism. Drawing from research by Alfred C. Redfield and G. Evelyn Hutchinson, Lovelock formulated that living organisms interact with the non-living environment to form a synergistic and self-regulating complex system, by co-evolving with their environment. He suggested that the whole system, including the biosphere, atmosphere, hydrosphere and pedosphere, seeks an environment optimal for life. This evolution is facilitated through a cybernetic feedback system that is unconsciously operated by the biota, leading to a final ‘state’ of full homeostasis.
While the Gaia hypothesis is generally accepted by many in the environmentalist community, there has been some criticism, particularly from the scientific community. Lovelock later made revisions to the hypothesis to clarify that there was no conscious purpose within this self-regulating system and to bring the hypothesis into alignment with ideas from other fields, such as systems ecology. This had reduced criticism, but there still remains scepticism from the scientific community.
Lovelock wrote more than 200 scientific papers as well as a number of books on a variety of topics within chemistry, environmentalism, geophysiology, climate change and more. Lovelock’s work has been recognised a number of times, receiving awards such as the Tswett Medal in 1975, the Dr A. H. Heineken Prize for Environmental Sciences in 1990 and the Royal Geographical Society Discovery Lifetime Award in 2001. He was also appointed a member of the Commander of the Order of the Britsh Empire for services to the study of Science and the Atmosphere in 1990 and a member of the Order of the Companions of Honour for services to Global Environmental Science in 2003. In 2006, he was awarded the Wollaston Medal, an achievement also received by Charles Darwin.
The European Parliament has voted to ban ‘fly shooting’ fishing in a part of the Channel. This technique, also known as demersal seigning, involves towing weighted ropes along the seabed at either end of a net, which then encircles and captures entire shoals of fish. Fly shooter vessels catch up to 11 times more fish than inshore fishing vessels and have a devastating effect on the marine ecosystem, biodiversity and local fishers. This decision is seen as a victory for small-scale fishers but it will also help reduce the damage caused to the seabed and marine ecosystems in the Channel.
UK households recycle only 12% of single-use plastics, disposing of nearly 100 billion pieces of plastic packaging a year. A new survey by Greenpeace is one of the largest voluntary research projects on the scale of plastic waste and it asked households to count their plastic waste for one week in May. Almost 250,000 people from around 100,000 households took part and showed that the largest proportion of plastic waste was from food and drink packaging at 83%. The most common item was fruit and vegetable packaging. On average, each household threw away 66 pieces of plastic packaging in one week.
Pollution
The Environment Agency (EA) is calling for water company bosses to be jailed for serious pollution. Shocking levels of pollution occurred in the last year, with 62 serious incidents of pollution in 2021. The EA has stated that chief executives and board members of companies responsible for the most serious incidents should be jailed and that courts should impose much higher fines. Only three water companies received the highest rating of four stars for their pollution performance. The rating takes into account the number and severity of pollution incidents, as well as self-reporting and the use and disposal methods of sewage sludge. Two companies, Southern Water and South West Water, were given the lowest rating of one star.
Conservation
3D printed reefs are being used to restore marine biodiversity. WWF Denmark and Ørsted have been testing how structures made of 70% sand and 30% pozzolanic cement (a combination of volcanic ash and portland cement) could be used to create new habitats for fish and other wildlife in the Kattegat strait between Denmark and Sweden. Twelve of these structures have been deployed between the wind turbines at Anholt Offshore Wind Farm, and it is hoped that they will help reverse the decline of cod stock in the Kattegat.
Bison have been released into the wild in the UK. Wild bison are ecosystem engineers and can help to restore biodiversity in woodlands through their natural behaviours, such as felling trees by rubbing against them and grazing. This is hoped to provide a nature-based solution to tackling the climate and biodiversity crisis. The releases are part of a five-year project led by Kent Wildlife Trust and the Wildwood Trust. The next steps include introducing Exmoor ponies, Iron Age pigs and Longhorn cattle.
Contraceptives are being given to grey squirrels in an attempt to control their population and allow red squirrel populations to improve. Grey squirrels are a non-native species first introduced from North America in the 19th century. They cause significant damage to UK woodlands as they strip the bark from trees, and they tend to target younger trees that are typically between 10-50 years old, either killing them or maiming them and leaving them vulnerable to pests and diseases. Culling has not been found to be a sufficient control measure, therefore it is thought that using contraceptives, which have longer-lasting effects, may be more effective.
Young Maori divers are hunting invasive crown-of-thorns starfish to save coral reefs. The species, also known as taramea, feed on coral reefs and, when there are too many individuals, can destroy reef habitats. Korero O Te `Orau, a local environmental organisation, has been training young Maori people in scuba diving to remove taramea from the reef and bury them inland. The recent outbreak of this species around the island of Rarotonga in the Cook Islands could jeopardize the survival of the surrounding coral reef if not tackled properly. More than 3,700 taramea have been collected so far.
Research
Great white sharks might change their colour when hunting prey. Researchers conducted experiments off of South Africa using a specially designed colour board with white, grey and black panels. Each shark was photographed as it jumped out of the water at the panels, with the experiment being repeated throughout the day. One particular shark appeared to be both dark grey and a much lighter grey at different times. The results were verified using computer software to correct for variables such as weather, light levels and camera settings. While the research has not yet been validated and published in a scientific journal, experts are still excited about the results.
The US Supreme Court has limited the Environmental Protection Agency’s (EPA) ability to curb power plant emissions, impacting America’s attempts to fight climate change.The Supreme Court ruled that the Clean Air Act does not give the EPA broad authority to regulate greenhouse gas emissions from power plants. The Biden administration plans to combat climate change by cutting the nation’s greenhouse gas emissions in half by the end of the decade and aiming for an emissions-free power sector by 2035. Now, the decision to curb power plant emissions must be taken by Congress itself, or “an agency acting pursuant to a clear delegation from that representative body.”
In other climate news, both Spain and Portugal are suffering the driest climate for at least 1,200 years, according to new research. Azores highs, high-pressure systems off the coast that blocks wet weather fronts in winter, have dramatically increased since 1980, pushing wet weather northwards. This is having severe implications for both food production and tourism. This change has been conclusively linked to increased anthropogenic emissions.
Scientists have warned Members of the European Parliament (MEPs) against watering down EU deforestation laws. Last week, a draft regulation was rewritten to define ‘forest degradation’ as the replacement of primary forests by plantations or other wooded land. As primary forests account for only 3.1m hectares of 159m hectares of overall forest, this definition would severely limit the law’s reach to only 2% of the total forest area. A letter from more than 50 scientists has stated that any exclusion of forest degradation from the law would undermine the EU’s desire for Europe to “become the first climate-neutral continent by 2050.”
Conservation
Bird flu has been confirmed at the UK’s only breeding colony of roseate terns in Northumberland. This “new virulent” form of bird flu is having a devastating impact on a number of wild bird species, with hundreds of seabirds found dead on Coquet Island. There are now calls for the government to develop and implement a national response plan for bird flu in wild birds, including clarity for collecting dead birds and a long-term plan for future threats. This disease is affecting all four species of tern on the island, as well as eider ducks, black-headed gulls and large gulls. The island is also home to nesting puffins but, so far, no puffin deaths have been recorded.
A £4.1m scheme has been revealed to improve wildlife habitats and alleviate flooding alongside roads in Stafford. The Stafford Brooks Project will target 25 locations near local rivers and streams to address the environmental impact of roads. Space will be created for wildflowers, trees and wildlife in areas where habitats have been impacted by activities from previous road building. New wetlands and reed beds are also being designed to help filter polluted run-off from roads, which can significantly impact river health.
Researchers are satellite-tracking whale sharks to explore the factors influencing their behaviour in the coastal waters of the Panamanian Pacific, including migratory and feeding behaviours. Rhincodon typus is vulnerable to population declines due to their slow maturation and they face a number of threats from humans, including entanglement in fishing nets and boat strikes. This study has shown that whale sharks spend more than 77% of their time in areas without any protection, indicating that conservation measures should go beyond the creation of local marine protected areas.
A new study, part-funded by The Mammal Society, has revealed the presence of plastic consumption in small mammals. More than 261 faecal samples were analysed to assess the exposure of seven terrestrial UK mammals to plastics. Four species, the European hedgehog, wood mouse, field vole and brown rat all had plastic polymers detected within their faecal samples. This ingestion was shown to occur across species of differing dietary habits and locations, confirming that plastic consumption is a widespread issue.
New Discoveries
A new giant water lily species has just been discovered, despite being in the archives of the Royal Botanic Gardens, Kew, for 177 years. Now holding the record as the world’s largest water lily, with its leaves growing more than 3m wide, the Victoria boliviana grows in a single water basin in part of the Amazon river system in Bolivia. It was long suspected to be different from the two other known giant species, V. amazonica and V. cruziana, but it was only when Kew grew all three side-by-side under exactly the same conditions that they could clearly see V. boliviana was totally different.
Policy
Singapore strengthened a law on Monday 4th July to stamp out wildlife trafficking, with stiffer penalties for those found guilty. The changes to the Endangered Species (Import and Export) Act include tripling the maximum jail term for individuals from two to six years and increasing the maximum fine from $50,000 (~£29,550) per species to $100,000 (~£59,100) per specimen. Companies involved in the trafficking of endangered species will also face higher fines and prison sentences, according to the Senior Minister of State for National Development, Tan Kiat How.
In the lead up to the 26th UN Climate Change Conference of the Parties (COP26) in November of last year, as well as the months that have followed, we have been writing a series of articles looking at some of the toughest global climate crisis challenges that we are currently facing. This post looks at the intensification of agricultural practices and how this can both be exacerbated by and contribute to climate change.
Farmer applying pre-emergence sprays. Chafer Machinery via Flickr
What is agricultural intensification?
Our global population is increasing year on year and is predicted to hit 10 billion by 2057. Agricultural production has to keep pace with the resource demands of this growing population. There are two main ways this can occur: an increase in the amount of land used for agricultural purposes or an increase in the yield from land already used through improvements or increased use of resources such as technology, fertilisers, labour, pesticides or scientific plant knowledge.
What are the impacts of land-use change?
Habitat destruction is considered one of the main causes of animal extinctions worldwide, and much of this destruction is due to clearing land for agriculture. Intensively managed agricultural land is far less valuable for the environment than natural habitats such as wetlands and forests. Intensively managed farmlands support less diverse and abundant species, sequester less carbon dioxide and suffer from increased water loss and soil erosion. Therefore, the increase in agricultural areas can contribute to climate change and worsen our ability to mitigate its effects.
Agricultural expansion and land clearing are pushed right up to Bwindi Impenetrable National Park boundaries in Uganda. USAID Biodiversity and Forestry via Flickr
What is the impact of increasing yields?
Intensification of agricultural management practices to increase yield includes an increase in the use of chemicals such as fertilisers, herbicides and pesticides, all of which can negatively impact wildlife, soil and nearby water quality. The artificial introduction of nutrients can be detrimental to the environment, particularly if it reaches waterways through run-off, as it can lead to algae blooms that can deplete aquatic oxygen levels.
Herbicides and pesticides have a direct impact on both target and non-target species, potentially disrupting populations and affecting whole ecosystems. Species can also be impacted through trophic poisoning, as the impacts of these chemicals can be heightened through biomagnification, where toxins build up in the food chain in greater and greater concentrations at each trophic level. This often results in the loss of top consumers which can destabilise ecosystems.
Another way to increase yield is by utilising as much of the existing agricultural land as possible. This, however, reduces the areas of non-crop species, such as trees and hedgerows. These areas represent essential diversity in plant species, helping to support a wide variety of fauna by providing food, shelter and breeding areas. Losing these areas reduces the variety and abundance of species that agricultural land can support. Additionally, crops are often grown in monocultures, a field composed of just a single crop species rather than multiple species, further reducing biodiversity. This increases the susceptibility of fields to disease and pest damage, furthering the need for additional chemical intervention.
Agriculture is one of the major sources of greenhouse gases that contribute to climate change. Methane and nitrous oxide, produced from livestock and as an indirect product of fertilisers, are particularly problematic. Increasing production or land area can increase the amount of greenhouse gases released into the atmosphere while reducing the amount of carbon that the land can sequester, enhancing the impact on climate change.
Climate change affects agriculture in return. Changes in precipitation patterns impact crop yields and reduce yield reliability. Higher temperatures, particularly heat waves, can lead to high yield losses, livestock death or sickness, a reduction in workable hours, increases in water supply needs and even damage to equipment. More frequent and higher intensity extreme weather, such as storms, can also impact in a similar way. Therefore, agriculture may not be able to keep up with food demands and would need to further increase its production. This could continue to drive climate change and exacerbate the impacts on agriculture in a cycle of detrimental effects.
What are the other options?
One solution is reducing food loss (by food suppliers) and waste (by retailers, food service providers and consumers). It is thought that, globally, around one-third of all food produced for human consumption is lost or wasted every year. This amounts to about 1.3 billion tonnes of food per year. When this is buried in landfills, it is broken down by microorganisms using anaerobic digestion, producing greenhouse gases (specifically methane and carbon dioxide), which are released into the atmosphere. Some countries, however, have begun to set up food recycling centres to capture these gases to be used as a renewable source of biofuel.
Food waste recycling plant in America. James Loesch via Flickr
By reducing the amount of food wasted, there would be less need to increase agricultural intensification to keep up with the growing population. This can be achieved through several routes, including changing the strict cosmetic standards of many retailers, providing better clarity on food expiration dates and bringing consumers’ attention to how much food they waste each year. For example, through a campaign called ‘Love Food, Hate Waste’, the UK had a 21% reduction in avoidable household waste between 2007 and 2012.
Sustainable farming practices are needed to ensure that global agriculture does not continue to seriously contribute to climate change. Through research into sustainable practices and better techniques, agriculture may be better able to provide enough food for the global population without compromising our environment. By reducing livestock numbers, increasing the efficiency of fertiliser application and better management for manure, the EU reduced agricultural emissions by 24% between 1990 and 2012. Additionally, the UK government is changing how they subsidise farmers. The Sustainable Farming Incentive, piloted by Defra, will reward acts that improve environmental outcomes and reduce carbon emissions. This should hopefully help to increase the sustainability of our agriculture, reducing its impact on climate change.
Another potential solution is regenerative farming, a practice that aims to reverse the impacts of and contribution to climate change by rebuilding soil organic matter and restoring degraded soil biodiversity. This results in an increase in carbon drawdown and an improvement in the water cycle. These farming practices include low- or no-till techniques, increasing plant diversity, introducing cover crops and crop rotations and minimizing physical disturbance. It also includes growing trees and shrubs around crops, using perennial crops that do not need to be replanted annually and creating borders of pollinator habitats. It is hoped that, by restoring the health of soils, farms will be able to increase their yield without negatively impacting the environment, reducing the need for agricultural intensification.
Tilling is used to aerate the soil, prepare seedbeds, suppress weeds, level soil, incorporate fertilisers and turn over cover crops. however, tilling contributes to soil erosion, surface runoff and carbon emissions. Image by United Soybean Board via Flickr
There is a concern, however, that the reduced tilling may lead farmers to rely more heavily on herbicides to remove unwanted plants. There may also be an increased use of fertilisers, to meet the need for nitrogen to convert carbon into microbial organic matter to allow it to remain sequestered in the soil. Questions have also been raised about whether regenerative farming can sequester additional soil carbon effectively, without decreasing yield or requiring more land for farming. For example if cover crops or additional trees and shrubs are added to farmlands without decreasing yield, then carbon sequestration will increase. However, if yield decreases and habitats such as a forest have to be cleared to replace lost production, then carbon sequestration will either remain the same or decrease.
COP26
There were several pledges and agendas launched at COP26 last year, including the Glasgow Leaders’ Declaration on Forests and Land Use, which intends to halt and reverse forest loss by 2030, reducing agricultural expansion into forest areas; and the Agriculture Innovation Mission for Climate (AIM4C), which looks to fund scientific breakthroughs, public and private applied research, and the development, demonstration and deployment of tactical, actionable and innovative products services and knowledge to producers. AIM4C has been criticised, however, for being over-reliant on technological solutions rather than sustainable farming methods. Other announcements including the climate emissions pledges and the Global Methane Pledge will also impact agriculture and its contribution to climate change, as countries look to introduce new regulations and policies to reduce emissions from farms.
The Koronivia Joint Work on Agriculture (KJWA) was also discussed at COP26. Originally established at COP23 in 2017, KJWA aims to bring discussions of agriculture into the UNFCCC and address agricultural issues through the lens of climate change. This process was set to end at cop26, but due to many areas of disagreement, the roadmap of how the Koronivia process will be going forward was included in the debate at the next meeting of the UN climate process, the Bonn Climate Change Conference, in June 2022.
Summary
Agriculture must keep up with the resource demands of an increasing global population. This is mainly achieved through increasing agricultural land or increasing yield. Both have negative environmental impacts and can contribute to climate change.
Climate change can also negatively impact agriculture, through changing precipitation patterns and extreme weather causing loss of crops and damage to equipment. This, then, requires more agricultural intensification to make up for losses, further contributing to climate change.
Solutions include more sustainable agricultural practices and reducing food waste. This reduces the impacts of agriculture on climate change while also reducing the need for more agricultural intensification. Other practices such as regenerative farming may help to improve soil health and carbon sequestration but there are criticisms about its effectiveness.
Several pledges launched at COP26 will impact agriculture and its contribution to climate change, including the Glasgow Leaders’ Declaration on Forests and Land Use, the Global Methane Pledge and the Agriculture Innovation Mission for Climate.
Useful resources:
The Food and Agriculture Organization of the United Nations’ (FAO) 2013 report: food wastage footprint: impacts on natural resources, illustrating how food is wasted or lost through various stages of the supply chain, highlighting the significant environmental costs.
The 2021 policy paper for the Sustainable Farming Incentive, piloted by the Department for Environment, Food & Rural Affairs (Defra).
A 2019 document outlining the National Farming Union of England and Wales’ (NFU) plans for achieving net zero, outlining the current impacts of agriculture and their goals for increasing sustainability.
Taking its title from a chilling warning made by the United Nations that the world’s soils could be gone within a lifetime, Sixty Harvests Left demonstrates why food and future harvests matter more than ever and shows us how we can restore our planet for a nature-friendly future.
Ian Newton discusses the changes that have occurred in British agriculture over the past seventy years, and the effects they have had on bird populations. He explains how different farming procedures have affected birds and other wildlife, and how an understanding of the processes involved could help in future conservation.
This book examines the climate, environmental, and human effects on agroecosystems and how the existing paradigms must be revised in order to establish sustainable production.
This multidisciplinary book presents state-of-the-art reviews of current SI approaches to promote major food crops, challenges and advances made in technology, and the institutional and policy measures necessary to overcome the constraints faced by smallholder farmers.
This book provides the first widely accessible overview of the concept of sustainable intensification as an innovative approach to agriculture and as a key element in the transition to a green economy.
This book examines over 30 years’ worth of research from the Allerton Project, a research and demonstration farm in the UK. Designed to provide guidance, feedback and recommendations to farmers, practitioners and policymakers, the Allerton Project is an exceptionally well-documented case study of lowland agricultural land management which has the purpose of meeting multiple objectives.
Abundance: Nature in Recovery is a collection of essays by award-winning author, Karen Lloyd. Examining abundance and losses in the natural world, Lloyd laments the lack of sight humanity has for the holes we have created. Looking first at artists such as Mary Newcomb, Carry Akroyd, and Daniel Beltrá, the book begins with the struggles of those trying to draw attention to the damaging impacts of human encroachment on the natural world. While many are beginning to understand the harm we are causing, the momentum of our modern society hasn’t allowed us to stop. By recounting a moment when a willow warbler flies into her house, Lloyd compares the fight of individual people against the systems we operate under with the panicked movements of the bird battering against the glass. We, like the bird, have no perception of how to remove ourselves from ‘the world of window frames and glass’ that we inhabit.
Abundance aims to give a voice to the species and habitats that are often disregarded in the political sphere. Travelling to places such as the Veluwe Forest in Switzerland, the Strathspey woodland in Scotland and the Hungarian Steppe, Lloyd tells the stories of people on the front line of conservation fighting to halt biodiversity loss. The volume of negative environmental news can often be overwhelming, and the author shares her own experience of this feeling in the opening essay. This book is a welcome break, reminding us that conservation success is possible and is taking place right now across Europe.
Through the exploration of local attitudes to conservation efforts, Lloyd touches on current themes such as rewilding and the return of wolves to the UK. Shifting baselines, where the current generation believes what they are seeing in nature around them is the norm and are unaware of the decline over previous generations, are impacting people’s perspective on the return of previously extinct species. Despite some extinctions being relatively recent, such as the beaver, the general public is unused to living with them. Therefore, they fear the impact these species may have on their daily lives. Worries of damage to livelihood and homes have been exacerbated by misconceptions and scapegoating. Lloyd recounts the concerns people have for the threatened wild salmon should beavers be allowed to remain, despite beavers being obligate herbivores, as well as the attempt to blame beavers for a flash flooding event in Alyth, Scotland. But if we are to allow the natural world to recover from the damage we have inflicted upon it, Lloyd believes that nature needs to be placed centre-stage in everything we do.
Wild salmon by Bureau of Land Management via Flickr
Abundance is an engaging and accessible book, presenting personal accounts of seeing firsthand the impacts of anthropomorphic destruction, riveting natural history stories and shocking data. From the conflict between the need for clean energy sources and the impacts of wind farms on birds to the impact of flood protection on beavers and kingfishers, Lloyd discusses our struggle to find effective solutions to tackle our biodiversity crisis. The engaging and entertaining nature of this book only increases as you read. Comparable to a travel book, each essay is a new adventure in wildlife-rich places. From eighty fragments on the pelican to tales from viewing platforms in the Lake District and the adventure of the 2020 lockdowns, the variety will hold your attention until the very end.
New Zealand farmers have suggested that the government should impose a levy on agricultural gas emissions to encourage the reduction of methane and nitrous oxide emissions. The government had legislated that farmers must develop an emissions pricing system or agriculture would automatically enter the country’s emissions trading scheme. Grassroots farms have been protesting in recent years against the introduction of environmental regulations, but agriculture currently generates over half of New Zealand’s industrial and household emissions. The sector has been facing significant political pressures over this disproportionate contribution to climate change.
Climate change is impacting whale habitat use in the Gulf of Maine. Warming waters has caused right and humpback whales to shift their use of Cape Cod Bay over the last 20 years. Using aerial surveys conducted from 1998 to 2018, the research team analysed environmental data to study changes in whale habitat use within and across years. The peak use of Cape Cod Bay by these species has sifted almost three weeks later, related to the arrival of spring, which has been changing due to climate change. Right whales may be using Cape Cod Bay for longer periods because climate change has reduced the amount of food available in other Gulf of Maine habitats.
A new study has estimated that 44% of Earth’s land is needed to stop the biodiversity crisis. Environmentalists have been lobbying governments to commit to protecting 30% of Earth’s land, but this may not be enough. A computer-generated global map has been created, showing the most efficiently marked amount of the typically needed territory of 35,561 species. This adds up to around 64 million square kilometres, which would require various levels of conservation management, from a strict ban on most human activities to regulations on sustainable development.
Scientists have used food puzzles to study how otters learn from each other. Using a combination of puzzle boxes and unfamiliar foods, the team observed that Asian short-clawed otters watched their companions and copied others when they sampled the unfamiliar food. This study aimed to understand how captive release otters would cope with unfamiliar food in their natural environments once they were released. The results suggested that if one otter was given pre-release training, it could pass some of that information onto other otters.
The Critically Endangered adult pine hoverfly (Blera fallax) has been seen in the wild in Britain for the first time in almost a decade. In October 2021 and March 2022, larvae were released at RSPB Abernathy and Forestry and Land Scotland Glenmore, bred as part of the Royal Zoological Society of Scotland’s conservation breeding programme. The pine hoverfly is an important part of forest ecosystems due to its role in both pollination and waste recycling.
A scientist from Newcastle University has rediscovered an ‘extinct’ giant tortoise on Fernandina, one of the Galápagos Islands. Through genetic testing of a female tortoise found in 2019 and a previous specimen found in 1906, the researchers found that the two were genetically linked and distinct from all other living species of Galápagos giant tortoises. Other expeditions to the island have found evidence of at least two or three more tortoises, which are hoped to be of the same species.
Microplastics
Scientists have found microplastics in freshly fallen Antarctic snow for the first time after collecting samples from 19 sites in Antarctica. An average of 29 particles per litre of melted snow was found, consisting of 13 different types of plastics. The most common, polyethylene terephthalate (PET), was found in 79% of samples. This plastic is primarily used in drinks bottles and clothing. While researchers suggested that the most likely source for these airborne microplastics is local scientific research stations, modelling has shown that their origin could be up to 6,000km away.
Researchers in the Canary Islands have discovered a new form of marine pollution that they have termed plastitar, a mix of tar and microplastics. This formation of two contaminants is an unassessed threat to coastal environments and could be leaking toxic chemicals, potentially proving deadly for organisms such as algae. There is concern that this formation may be blocking and inhibiting the development of the ecosystem.
Policy
No-anchor zone in Studland Bay has been extended to save seagrass habitats. The scheme, set up in December, was introduced to stop anchors dropping and damaging the seagrass meadows. However, there is concern that this voluntary scheme is not being advertised enough to sailors and that there are not enough eco-moorings, an alternative to conventional anchors that do not scour the seagrass.
This guide includes an introduction covering how to attract insects to your garden, advice on photographing insects, a description of insect anatomy, the characteristics of the insect orders included in the guide, and the insect lover’s year, describing the best places to look for different species throughout the different months and seasons of the year.
From there, each species is presented, grouped by order, with keenly observed descriptions to help you identify even the smallest creature, as well as one or two photographs labelled with distinguishing features. In each of these sections, there are details of its life cycle from egg to adult, a calendar showing the time of year when the adult can be seen, and star facts that give further proof of insects’ fascinating lives.
Using the guide
Throughout March, April and May, we tested the identification guide by exploring a garden for a few hours during the day and during the night. The garden is small, with a patch of lawn, bare dirt, a hedgerow of mainly ivy (Hedera helix) and holly (Ilex aquifolium), stone gravel, Japanese camellia (Camellia japonica) and rhododendron (Rhododendron sp.) bushes, a field maple tree (Acer campestre), clumps of daffodils (Narcissus pseudonarcissus) and three-cornered garlic (Allium triquetrum), as well as various other flowering and non-flowering plants. This garden also contains a small insect house which was placed in September of last year. Weedkiller was used once in September but no other chemicals have been used since, nor has the lawn been mowed. Therefore, the garden should be able to support a number of insect species. We attempted to search by eye and by using a tapping tray and stick. Compared to just searching by eye, we found that we had little success with tapping as the vast majority of what we found were spiders and we were unable to identify the few insect species we found using this guide.
What we found
Marmalade hoverfly by H. Ketley
Following the guide, we were able to ID this species as a marmalade hoverfly (Episyrphus balteatus), a small, delicate hoverfly with a unique pattern of twin dark bands separated by lighter bands. As this individual doesn’t have ‘holoptic’ eyes – eyes that meet at the top of the head – we believe this is a female.
Speckled wood by H. Ketley
This guide has a large section on butterflies and moths, covering a number of common species you’ll likely see in your garden and local green spaces. This species is a speckled wood (Parage aegeria), identifiable through its dark colouration and the spots on its hindwing, which have a yellow outer ring, a black inner ring and a white central spot. According to the guide, it is a distinctive species, and there are no similar species listed. However, for those unfamiliar with these species, their underwing pattern could potentially be confused with other butterflies such as walls (Lasiommata megera) or graylings (Hipparchia semele).
Dock bug by H. Ketley
This is a dock bug (Coreus marginatus), a small insect from the family Coreidae. According to the guide, they’re common and widespread in Europe, but in Britain, Ireland and Scandinavia, they’re restricted to the southern parts. They’re identifiable through their shape (upturned, pointed pronotum and broad abdomen with a noticeable scutellum), their red-orange antennae with a black final segment, and their pale-brown colouration. There is variation in the wing membrane colour between individuals, and an important diagnostic feature that can distinguish it from other similar species is the forward-pointing spines between its antenna. This feature can be most easily identified using a hand lens, handheld magnifier or magnifying pot.
Green shieldbug by H. Ketley
This similar-looking species is a (common) green shieldbug (Palomena prasina). Despite its name, this species can range from bright green to bronze, particularly becoming darker prior to winter hibernation. Its brown wing membranes set it apart from similar, non-native species, such as the southern green shieldbug (Nezara viridula), as noted in the guide. If you are able to look closely at one, you’ll be able to see it is covered in tiny black dots, with red eyes, feet and antennae (primarily the last two segments). It can also have a red edge all the way around its thorax and abdomen.
Common malachite beetle by H. Ketley
We also managed to spot this colourful species, which we were able to ID using the guide as a common malachite beetle (Malachius bipustulatus). The red ‘shoulders’ and red spots on the end of the abdomen, helpfully annotated in the guide’s photo, made this species easy to identify.
Using this guide, we were also able to identify a scorpionfly, bluebottle, greenbottle, dark-edged bee-fly, thick-legged flower beetle, two-spot ladybird and a buff-tailed bumblebee.
Our opinion
As noted in the introduction to this guide, there are around 24,000 insect species in Britain, and almost three times that in mainland Europe. And so there will always be species you find in your garden that are not in this field guide, which covers only 150 species. The breadth of the species covered within the guide perhaps could’ve been expanded, but as it does cover many of the most common species, you are still likely to see a number of these species within your garden and local green spaces. In addition, the paired-down number of species can be useful, as it can be quicker and easier for readers to accurately identify species they’ve found. Therefore, this is still an incredibly useful guide, particularly for naturalists, beginners and those who want a more concise and affordable insect field guide.
Climate change is weakening trees. Conditions such as extreme heat and drought can impact tree growth, potentially encouraging the formation of shallow root systems. These conditions can also increase the chances of tree diseases thriving. This, along with the potential impact of development, such as road management which damages root systems, is reducing the resilience of trees to stresses such as adverse weather, increasing the likelihood of storm damage.
Climate change and development are weakening trees. Image by Padraic via Flickr
A vulnerable coral species, the pink sea fan, may be likely to spread northwards due to climate change. The species, found in shallow waters from the western Mediterranean to north-west Ireland and south-west England and Wales, is a species of principal importance in England and Wales. A new study, run by the University of Exeter, found that there will likely be an increase in suitable habitats for this species northwards, with existing habitats remaining suitable over the next 60-80 years. The results of this study could hopefully be used to identify areas that are a priority to protect the coral.
Policy
Peatlands are still being burnt, despite the new government ban. Peatlands deeper than 40cm are protected from burning by the new ban introduced last year. However, the RSPB has sent the government evidence of 79 fires that they believe are in breach of these new regulations. Both the RPSB and Greenpeace are calling for a blanket ban on the burning of all peat, regardless of depth. Peatland deterioration has been linked with the release of almost 3.7 million tonnes of carbon dioxide each year in the UK.
Research
New research has shown that sounds can be used to monitor the health of coral reefs. Monitoring the pops, clicks and clacks produced by fish and other marine life can be a non-intrusive, inexpensive and efficient method of tracking the state of coral reefs. Reduced biodiversity in degraded communities results in less activity, and so these reefs do not sound as loud compared to healthy ones. By monitoring decibel levels and comparing soundscapes using underwater microphones, researchers may be able to plan conservation interventions and monitor restoration projects on a long-term basis.
Coral reef sounds could be used to monitor ecosystem health. Image courtesy of Tiket2 via Flickr
A variety of targeted conservation approaches are needed to protect UK bumblebee species. A study, using 10 years of data from Bumblebee Conservation Trust’s citizen science scheme BeeWalk, has found that a ‘one-size-fits-all’ approach to bumblebee conservation may not be an effective method, as there is a wide range of differences between species in the types of habitats they are associated with. Instead, conservation efforts would be better served by being carefully tailored to particular species.
Diatoms, the most important producers of plant biomass in the ocean, could decline due to ocean acidification. These calcifying organisms were previously thought to benefit from ocean acidification as they rely on silica rather than calcium carbonate to build their shells, however, a new study suggests diatom populations could drastically decline. Ocean acidification causes the silicon shells of these species to dissolve more slowly, causing them to sink to deeper water layers. In these layers, these shells chemically dissolve and are converted back to silica. Because of this, the abundance of silica is reduced in the surface layers where new shells are formed, resulting in a decline in diatom populations.
The Marine Stewardship Council, an organisation that certifies fisheries under its blue tick sustainability label, has ordered an independent investigation into allegations of shark finning on tuna vessels in certified Pacific fisheries. Between 2019 and early 2020, reports state that silky sharks and a black-tipped reef shark had their fins cut before being discarded overboard. Both species are classified as Near Threatened.
In other shark news, Grey nurse sharks are thought to be thriving at a popular dive site in Australia, but there are calls for more research into this critically endangered species. Only around 2,000 individuals are estimated to be left in the wild, following persecution during the 1960s and 70s inspired by the movie Jaws. Bass Point, where a large number of grey nurse sharks were counted, was removed as a critical habitat site in 2013. Conservation biologist Adam Stow, who has been studying this species for nearly 20 years, says more research is needed into the impact of climate change on their movements.
Work begins to turn 99,000 hectares in England into ‘nature recovery’ projects. Five landscape-scale projects in the West Midlands, Cambridgeshire, the Peak District, Norfolk and Somerset are aiming to help tackle wildlife loss and the climate crisis, while also improving public access to nature. The proposed projects range from transforming farmland into chalk grassland to restoring dewponds and sustainably managing wetlands.
Agricultural Development and Sustainable Intensification
