The window for a livable future is closing, warns IPCC

The breakdown of earth’s climatic system is accelerating rapidly and many of the impacts will be more severe than previously predicted, global scientists have said in the most recent report from the Intergovernmental Panel on Climate Change (IPCC).

The world is already experiencing widespread and dangerous water shortages, extreme heat, melting ice caps and glaciers, wildfires and flooding as a result of human greenhouse gas emissions, the report shows, warning that “any further delay in concerted global action will miss a brief and rapidly closing window to secure a liveable future”.

Focusing on physical impacts, human vulnerabilities and adaptation, today’s report is the second part of the IPCC’s latest comprehensive climate assessment, the sixth such exercise since the organisation was founded in 1988. It follows an earlier report, released last August, on the physical science of global heating. That report showed that atmospheric concentrations of CO2 are now higher than any time in at least two million years, with the earth now 1.1ºC hotter than in pre-industrial times as a result.

IPCC assessments contribute heavily to the risk assessments, stress tests and scenario analysis carried out by central banks, financial supervisors and financial institutions. They also form the basis of the climate scenarios for central banks and supervisors developed by the Network for Greening the Financial System.

IPCC assessment reports contain the conclusions of hundreds of specialised scientists from around the world working over many years, and are approved by the governments of 195 member nations. Because of the long timescales involved in producing the assessments, this is likely to be the last such exercise while the opportunity to stay within the Paris Agreement’s 1.5ºC target still exists.

The human, social and economic consequences of breaching that target will be severe, the report finds.

Allowing global temperatures to increase beyond 1.5ºC would result in “irreversible” impacts, including the melting of ice caps and glaciers. Such temperatures would also significantly increase the probability of climate system tipping points. Tree die-offs, drying peatlands, thawing permafrost and other self-reinforcing feedback loops release additional carbon emissions, amplifying the warming further which spirals beyond the ability of humanity to influence.

The report also finds that:

• the past five years have been the hottest on record since 1850;
• half the global population live in areas “highly vulnerable” to climate change;
• even at current levels of heating, millions of people face food and water shortages;
• in some regions adaptation will be impossible if global warming exceeds 2°C;
• mass die-offs of trees, corals and other species as a result of climate change are already under way;
• key ecosystems are losing their ability to absorb carbon dioxide, turning them from carbon sinks to carbon sources;
• many changes due to past and future greenhouse gas emissions cannot be reversed for centuries to millennia, especially changes to the ocean, ice sheets and global sea levels.

“Increased heatwaves, droughts and floods are already… occurring simultaneously, causing cascading impacts that are increasingly difficult to manage,” the IPCC said in a press release accompanying the report. “They have exposed millions of people to acute food and water insecurity. 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.”

The third IPCC report in the current assessment will be released in early April and will focus on how humanity can mitigate the unfolding climate crisis.