Climate change is causing widespread loss and damage to lives, livelihoods, homes and natural habitats – with more severe effects to come, the UN has said.
Already some of the impacts of global warming are irreversible, as nature and humans are pushed to the limits of their ability to adapt to rising temperatures, the Intergovernmental Panel on Climate Change (IPCC) said.
Any further delays to curb greenhouse gas emissions and adapt to already inevitable climate change will see humanity miss a “brief and rapidly closing window” to secure a liveable and sustainable future, the report warns.
UN Secretary-General Antonio Guterres described the report as “an atlas of human suffering and a damning indictment of failed climate leadership”, warning that nearly half of humanity is in the climate danger zone and many ecosystems are at the point of no return.
The assessment is the second in a series of three reports from the IPCC in the latest review of climate science, which take place every seven years or so for governments.
It has been released after its summary was approved line by line in a process involving representatives of 195 governments and scientists, and looks at the impacts of climate change, efforts and limits to adapt to rising temperatures and vulnerable communities and natural systems.
The report finds that climate change caused by humans has led to increasing heat and heatwaves, rising sea levels, floods, wildfires, heatwaves and drought, causing death, food and water scarcity, and migration.
Humanity does have the capacity to respond to a crisis and this report is a call to actionProfessor Rachel Warren, UEA
Health impacts have been felt worldwide: people have died and suffered illness from extreme heat, diseases have emerged in new areas, there has been an increase in cholera, and worsening mental health, with trauma inflicted by floods, storms and loss of livelihoods.
Global warming has caused substantial damage and increasingly irreversible losses to natural systems, such as mass die-offs of corals and trees, and the first climate-driven species extinctions.
Different weather extremes are happening at the same time, causing “cascading” effects that are increasingly hard to manage.
Some 3.3 billion to 3.6 billion people live in situations where they are highly vulnerable to climate change, the report warns.
The consequences of global warming, which has reached 1.1C above pre-industrial levels already, are not felt evenly around the world, with countries in sub-Saharan Africa and small island states among the most at risk.
But even in the UK and Europe people face coastal and inland flooding, heat extremes, damage to habitats, water scarcity and loss of crop production, as well as knock-on effects on food supplies and prices.
There will be “unavoidable increases” in climate hazards in the next two decades with global warming of 1.5C above pre-industrial levels, the bleak 35-page summary for policymakers says.
Professor Rachel Warren, from the University of East Anglia, and lead author of one of the report’s chapters, said it “finds high and very high risks at lower global warming levels than in the last assessment,” with a high risk of extreme weather at 2C of global warming.
She said the number and intensity of extreme weather events had been increasing around the world, including in the UK and Europe.
For the UK, she said: “The most obvious thing that people will notice is more heatwaves and more floods being the two that we experience in the UK in particular, and also there is a risk of more drought in the UK.”
And if the world exceeds the 1.5C threshold, even for just a few decades, there will be severe and potentially irreversible impacts such as increases in tree mortality and fire, species losses, rapid and irreversible Antarctic ice sheet melt, and coral reefs are unlikely to survive.
Prof Warren acknowledged the report was bleak, with a hard message, but said there was also hope.
“Humanity does have the capacity to respond to a crisis and this report is a call to action,” she said.
Climate change isn’t lucking around the corner, waiting to pounce, it’s already upon us, raining down blows on billions of peopleInger Andersen, UNEP
The report said accelerating efforts to adapt to climate change – which are currently patchy and insufficient – is urgently needed and can help.
But it warns there are limits to how much people and nature can cope with, making curbing emissions to limit temperature rises also crucial.
The report, which comes just over 100 days after world leaders agreed new efforts to limit warming to 1.5C to avoid the worst climate impacts and to deliver finance for adaptation at the Cop26 summit in Glasgow, calls for adequate funding to help those most at risk.
As the report was launched, UN leaders lined up to call for action, with World Meteorological Organisation (WMO)secretary-general Prof. Petteri Taalas, warning the atmosphere was “on steroids, doped with fossil fuels” driving more extreme weather with high human and economic impacts.
United Nations Environment Programme (UNEP) executive director Inger Andersen said: “Climate change isn’t lucking around the corner, waiting to pounce, it’s already upon us, raining down blows on billions of people.”
She said: “We need to soften and slow the blows by cutting greenhouse gas emissions, but we also need to cushion the blows by picking up our efforts to adapt to climate change, which have been too weak for too long.”
Restoring and conserving nature was the best way to do this, she said.
The report set out options to safeguard nature to help curb emissions and protect against climate impacts, including conserving 30%-50% of the world’s land, freshwater and oceans, restoring wetlands, nature-friendly farming and more plant-based diets to reduce pressure on land.
But it warns against “maladaptation” – efforts to adapt such as hard sea walls which can cause more problems – and geoengineering schemes that could cause a host of new risks.