Climate risks laid bare
Authors: None The Lancet Planetary Health
Journal: The Lancet Planetary Health (2022)

In August last year, the IPCC released the first of its periodic Assessment Reports (IPCC AR6 WG1), which summarised the available evidence on the physical science of climate change. That report broadly described increased scientific confidence in how the Earth system is changing in response to human activities, enabling a headline statement that “It is unequivocal that human influence has warmed the atmosphere, ocean and land. Widespread and rapid changes in the atmosphere, ocean, cryosphere and biosphere have occurred.” UN Secretary-General António Guterres called that report “a code red for humanity”. In February this year, the IPCC AR6 Working Group 2 (WG2) report on “climate impacts, adaptation and vulnerability” was released. This report typically gets less media attention than the WG1 report, perhaps because it is always published afterwards, and this year understandably it has been somewhat eclipsed by coverage of the war in Ukraine. In many ways though the WG2 report is the one that describes the aspects of climate change people experience and care about most. The report looks at the complex ways that climate change is posing risks for nature and people, now and into the future. It also presents options for how we might seek to minimise the negative impacts of climate change through adaptation. The WG2 report is both unsurprising, building as it does on the evidence base used in earlier reports and the latest scientific research, and yet startling in the risks that are revealed. As António Guterres put it at the report press conference “Today's IPCC report is an atlas of human suffering and a damning indictment of failed climate leadership… with fact upon fact, this report reveals how people and the planet are getting clobbered by climate change.” As with the WG1 report, much of the development can be summarised as broadly improved confidence as the evidence is now much stronger in many areas of impacts, adaptation, and vulnerability. This greater confidence also reveals that climate risks are generally appearing faster and are expected to get more severe sooner than previously reported. The scope of the report is huge and cannot be effectively summarised here, but there are some noteworthy findings worth pulling out. The report places much more explicit emphasis on the interconnections between people, nature, and climate. This includes better estimates of species extinction risks resulting from climate change. Globally, the percentage of species at high risk of extinction is estimated to range from 9–14% at 1·5°C to 13–39% at 4°C. There is also very high confidence that changes in species’ geographical ranges and the timing of life cycle events, such as tree bud burst, are already linked to climate change. The report concludes with high confidence that effective and equitable conservation of approximately 30–50% of Earth's land, freshwater, and ocean areas is needed to maintain resilience of biodiversity and the ecosystem services on which we depend. Although climate change is impacting every country, the most severe negative effects are generally occurring in the poorest countries, who have the least capacity to adapt to these changes and have contributed least to the problem in the first place. The report suggests that about 3·3–3·6 billion people are highly vulnerable to climate change. For the first time, climate change is shown to be already contributing to humanitarian crises and climate and weather extremes are increasingly driving displacement. There is also very high confidence that “Climate-related illnesses, premature deaths, malnutrition in all its forms, and threats to mental health and wellbeing are increasing”. Perhaps most concerningly, climate change impacts and risks are shown with high confidence to be becoming increasingly complex and more difficult to manage. Multiple climate hazards are expected to occur simultaneously, with multiple climatic and non-climatic risks interacting, resulting in compounding overall risk and risks cascading across sectors and regions. Projected adverse climate impacts and related losses and damages escalate with every increment of global warming. The message is unequivocal; greatly accelerated mitigation and adaptation measures are required immediately to secure a healthy planet for healthy people. Unfortunately, this huge intellectual effort to synthesise the evidence is unlikely to be enough, on its own, to sufficiently catalyse action. We urge readers to dip into the report and understand the depth of the challenges we face. If you do, it will be hard not to make this a pressing personal and professional priority.