Sustt: temperature records, elephant diets, and ecological tipping points

Stat of the week ??

On July 4, 2023, the average global air temperature recorded 2 meters above the Earth's surface reached 17.18°C (62.92°F), breaking the previous record of 17.01°C (62.62°F) set on July 3. This marks the hottest day ever recorded on Earth since instrumental measurements began in the 1850s. The consecutive days of record-breaking heat confirm predictions that 2023 will be one of the hottest years on record, driven by climate change and a warming El Ni?o climate pattern. The warming in the Pacific Ocean, signalling the onset of an El Ni?o event, is a significant contributor to the high global temperatures observed. (New Scientist)?

Europe is warming faster than any other continent - read our in-depth insight here.

Bite-sized insights

What else we're seeing this week ??

?? Forever chemical lawsuit –?US conglomerate 3M has agreed to pay up to $10.3bn over 13 years to settle multiple lawsuits relating to the contamination of US water supplies. The company, which is one of the largest manufacturers of PFAS, will provide financial compensation to public water suppliers that have found the chemicals, also known as “forever chemicals”, in their drinking water. The settlement will support the suppliers in testing and treating water contaminated with PFAS. In a statement, 3M expressed its commitment to environmental responsibility and confirmed its plans to discontinue all PFAS manufacturing by the end of 2025. (The New York Times)?

?? Reducing shipping emissions –??Shipping emissions could be cut by 50% by 2030 using existing techniques and innovative technology, including hydrogen, without significantly undermining trade, according to research by consultancy CE Delft. The report comes as the International Maritime Organization (IMO) meets in London for talks on the possibility of introducing a levy of up to $100 per tonne of carbon generated by ships. Marine transportation is responsible for approximately 3% of global greenhouse gas emissions. The industry has been slow to adopt emissions-reducing technologies and there are currently few alternatives to the cheap, dirty diesel oil used in vessels. (The Guardian)

?? Elephants like a varied diet, just like us –?A study conducted by Brown University and published in the journal Royal Society Open Science reveals that elephants exhibit surprising variation in their dietary habits from meal to meal. The researchers used innovative methods, including DNA metabarcoding, to analyse the specific types of plants eaten by individual elephants in two groups in Kenya. The study highlights the importance of understanding individual dietary preferences to effectively manage and conserve iconic species like elephants. By providing a variety of food sources, conservation efforts can ensure the well-being and sustainable growth of elephant populations while minimising inter-species competition and crop poaching. (Science Daily)?

In-depth insight ??

Ecosystems could collapse more quickly than previously thought

By Claire Pickard, Sustainability Specialist: "There is much controversy about action on climate change in the UK at the moment with both political parties facing criticism for allegedly reneging on previous pledges. Just last week, Lord Deben the outgoing chair of the Committee on Climate Change, said that young people would not forgive those who failed to act effectively on this issue. This study's warning that the current generations could be the last to see the Amazon rainforest really brought home to me the urgency of the situation – and how very little time we have left to avoid disastrous tipping points."

What’s happening??Ecological collapse is likely to occur more quickly than previously thought, according to research by UK scientists. The analysis found that over 20% of global ecosystems, including the Amazon rainforest, could break down within a human lifetime. The study, which modelled how tipping points could accelerate each other, examined two lake ecosystems and two forests. The researchers found that up to 15% of collapses happened due to new stresses or extreme events, even when the primary stress level remained constant. This means that even if sections of an ecosystem are managed sustainably, new stresses, including climate change, could precipitate collapse. (The Guardian)

Why does this matter??The research,?published?in Nature Sustainability, is likely to prove highly controversial. The scientific understanding of tipping points, and the ways in which they?interact?with one another, remains undeveloped. The UN’s Intergovernmental Panel on Climate Change (IPCC), its leading science advisory body, remains cautious in its assessment of their impact. In its latest report, the IPCC?estimated?the earliest date of a potential Amazon tipping point as 2100.

Sooner rather than later –?However, Brazilian scientists, including leading Amazon expert Carlos Nobre, have?warned?that such a tipping point could occur much sooner than the IPCC predicts – an argument supported by the new UK study. Research by insurance company Swiss Re in 2020 also found that one-fifth of countries are at?risk?of ecosystem collapse due to wildlife and habitat destruction. The report argued that the risk of tipping points is?growing, posing a threat to the more than half of global GDP ($42tn) that depends on high-functioning biodiversity.

Writing in The Conversation, the authors of the new study argue that previous studies have suggested that “regime shifts” are taking place in over 20 different types of ecosystem where tipping points have been?exceeded. Regime shifts are “large, persistent?changes?in the structure and function of social-ecological systems”. Examples include rainforests being?transformed?into savanna or icy tundra thawing. Such shifts are?caused?when ecosystems are placed under stress by human activities such as pesticide use, development, and soil and waterway pollution. Globally, over 20% of ecosystems are now at?risk?of collapse or transformation.

The new study argues that most previous studies have?focused?on a single driver of destruction, such as deforestation or climate change. However, when such drivers are combined with other threats, including water stress, degradation and river pollution linked to mining, breakdown occurs more quickly.

What’s in the study??The researchers used two general models,?representing?forests and lake water quality, and two location-specific models,?based?on India’s Chilika lagoon fishery and Easter Island (Rapa Nui) in the Pacific Ocean. Software was then used to model over 70,000 different simulations. Stress and extreme events advanced the date of an anticipated tipping point by 30-80% across all four models.

Professor Simon Willcock of Rothamsted Research, who co-led the study,?cites?the example of Lake Erhai in China, which collapsed sooner than expected. Willcock claims this is because most projections were based solely on agricultural runoff that was causing excess nutrients in the water system. However, the combination of climate variation, water management and other pollution meant that the lake lost resilience more quickly than predicted.

Not too late?–?Willcock added that while the study’s conclusions were “devastating,” they also?indicated?that small improvements could have major repercussions. Although the research focused on negative impacts, system dynamics meant that the application of positive pressure could result in “rapid recovery”.

The researchers said that their findings showed that policymakers?needed?to act with greater agency. Otherwise, Willcock claims, “We could realistically be the last generation to see the Amazon”.

Read more insight on the Susst blog.

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