Climate change

Human-induced climate change is causing dangerous and widespread disruption in nature and affecting the lives of billions of people around the world, according to a new report co-authored by a University of Plymouth researcher.

The Summary for Policymakers of the IPCC Working Group II report, Climate Change 2022: Impacts, Adaptation and Vulnerability was approved on Sunday, February 27 by 195 member governments of the Intergovernmental Panel on Climate Change (IPCC).

It highlighted that the world faces unavoidable and multiple climate hazards over the next two decades with global warming of 1.5°C (2.7°F).

The report also says that even temporarily exceeding this warming level will result in additional severe impacts, some of which will be irreversible. Risks for society will increase, including to infrastructure and low-lying coastal settlements.

Professor Camille Parmesan, from the University’s School of Biological and Marine Sciences, has been a Coordinating Lead Author for Working Group II of the 6th Assessment Report of the IPCC for the past four years. She coordinated a global assessment of observed and projected impacts of climate change on terrestrial and freshwater ecosystems and their adaptation options.

She was also heavily involved with chapters linked to her ongoing research, including: observed impacts on wild species of current and future climate change; population losses, mass mortality events of plants and animals, and species' extinctions driven by climate change; changes in diseases in wildlife due to climate change and how that relates to changing risks for humans; and the potential of natural ecosystems in helping humans mitigate and adapt to climate change, includes the roles of Nature-based Solutions and of Ecosystem-based Adaptation.

Professor Parmesan, who also is a Make Our Planet Great Again Laureate and has affiliations to the French National Centre for Scientific Research (CNRS) and the University of Texas at Austin, said:
“Since our last Assessment Report in 2014, the impacts of climate change have risen exponentially. Effects have been documented in every region of the planet, and they are occurring sooner and are more negative than previously expected. Adverse impacts also far outweigh the positives, including for agricultural production and human health. Species have shifted where and when they live, attempting to track climate as it shifts is space and time. 
Professor Camille Parmesan
Professor Camille Parmesan
"We are also starting to see the first global extinctions driven by climate change, and that is an irreversible impact. It will also affect human populations as new evidence in this report documents the strong coupling between ecosystem health, human health and well-being, and sustainable development for society.
Professor Parmesan added:
"There is an urgent and pressing need for action, and the potential solutions are out there. However, a key message from this report is that we must plan for change. The current projections represent a range of possible futures, and the decision-making process will be most effective and most resilient to climate change when it retains flexibility and is open to changes in planning as climate change occurs in real time.”
Among the key elements specific to the UK highlighted in the report are that peatlands, such as those found on Dartmoor and other parts of south west England, are one of the highest carbon systems in the world and essential for carbon sequestration and storage. 
Professor Parmesan said:
"Climate change is causing some peatlands to become drier, causing them to release carbon as they decompose. In some systems in some regions (such as parts of the high Arctic permafrost), these processes have already gone so far as to shift these high-carbon systems from being historical carbon sinks into new carbon sources. This weakening of the biosphere's ability to suck up and store carbon from the atmosphere is one of the most worrying risks from ‘overshoot’ – that is, allowing global warming to exceed 1.5 or 2°C for several decades.
She added:
“We can control how much humans contribute to global warming through mitigation actions, but it will become increasingly harder to control the biosphere as it increasingly shifts from removing carbon-dioxide from the atmosphere to releasing it back into the atmosphere. And the peatlands are also a key example of why planting trees everywhere is not a good idea. If you drain peatlands and plant trees, this causes the dry peat soils to decompose and releases far more carbon than the trees remove as they grow. This is a perfect example of ‘maladaptive’ mitigation actions."

It also featured details of heatwaves being associated with outbreaks of helminth pathogens, which have expanded or shifted their ranges poleward due to increases in temperature, precipitation and humidity. These pathogens can reduce growth and yield, kill livestock and infect humans and wildlife, leading to health, agricultural and economic losses.

Urgent action required to deal with increasing risks

The IPCC’s Working Group II is composed of around 220 scientists from a variety of disciplines and specialisations, representing all regions of the world. Its report is the second instalment of the IPCC’s Sixth Assessment Report (AR6), which will be completed this year.

Among the key findings are that increased heatwaves, droughts and floods are already exceeding plants’ and animals’ tolerance thresholds, driving mass mortalities in species such as trees and corals.

These weather extremes are occurring simultaneously, causing cascading impacts that are increasingly difficult to manage. 

They have exposed millions of people to acute food and water insecurity, especially in Africa, Asia, Central and South America, on Small Islands and in the Arctic.

The report says that to avoid mounting loss of life, biodiversity and infrastructure, ambitious, accelerated action is required to adapt to climate change, at the same time as making rapid, deep cuts in greenhouse gas emissions.

So far, progress on adaptation is uneven and there are increasing gaps between action taken and what is needed to deal with the increasing risks, the new report finds. These gaps are largest among lower-income populations.

Hoesung Lee, Chair of the IPCC, said:

“This report is a dire warning about the consequences of inaction. It shows that climate change is a grave and mounting threat to our wellbeing and a healthy planet. Our actions today will shape how people adapt and nature responds to increasing climate risks.”

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