Eight years after its last full update on climate science, the United Nations on Monday published a report that delivered even starker warnings about how human-induced climate change is affecting the planet – and how damaging the impacts might get.
The UN Intergovernmental Panel on Climate Change (IPCC) said human influence was "unequivocally" to blame for warming the planet, and that some forms of climate disruption were now "locked in" for centuries.
Without rapid and large-scale reductions in emissions, the report said, the average global temperature will exceed critical thresholds of 1.5 and 2.0 degrees Celsius (2.7 and 3.6 degrees Fahrenheit) during the 21st century.
Here are some early reactions to the IPCC report.
GOVERNMENTS, COUNTRIES, UN
United Nations Secretary General Antonio Guterres:
"Today's IPCC Working Group 1 Report is a 'code red' for humanity. The alarm bells are deafening, and the evidence is irrefutable: greenhouse gas emissions from fossil fuel burning and deforestation are choking our planet and putting billions of people at immediate risk. Global heating is affecting every region on Earth, with many of the changes becoming irreversible ...
"This report must sound a death knell for coal and fossil fuels, before they destroy our planet."
British Prime Minister Boris Johnson:
"Today's report makes for sobering reading, and it is clear that the next decade is going to be pivotal to securing the future of our planet. We know what must be done to limit global warming – consign coal to history and shift to clean energy sources, protect nature and provide climate finance for countries on the frontline ...
"I hope today's IPCC report will be a wake-up call for the world to take action now, before we meet in Glasgow in November for the critical COP26 summit."
US Special Presidential Envoy for Climate, John Kerry:
"As the IPCC makes plain, the impacts of the climate crisis, from extreme heat to wildfires to intense rainfall and flooding, will only continue to intensify unless we choose another course for ourselves and generations to come.
"What the world requires now is real action. All major economies must commit to aggressive climate action during this critical decade."
Diann Black-Layne, Ambassador of Antigua and Barbuda, Lead Climate Negotiator for the Alliance of Small Island States:
"Major emitters must take account for the damages inflicted by the fossil fuel industry, knowing that every single tonne of carbon and every single dollar spent on fossil fuels will have a negative impact ...
"The stark fact is that if we keep warming to 1.5C, we are still facing half a metre of sea level rise. But if we stop warming from reaching 2C, we can avoid a long-term three metres of sea level rise. That is our very future, right there."
Mohamed Nasheed, ambassador for the Climate Vulnerable Forum of 48 countries, and former Maldives president:
"Our people are dying in vulnerable developing countries because of the fossil fuel burning for consumption and economic growth in rich countries. We are paying with our lives for the carbon someone else emitted. We will take measures soon to begin to address this injustice, which we cannot merely accept."
Paulo Artaxo, an IPCC lead author and environmental physicist at the University of Sao Paulo:
"This is a strong message that we are changing the climate in an irreversible way. So basically, we are damaging the climate in such a way for the next generations that this will certainly make the socioeconomic difficulties in the future much, much worse than in our generation ...
"My personal opinion is that it will be impossible to limit the increase in temperature to 1.5 degrees."
Friederike Otto, an IPCC lead author and Associate Director of the Environmental Change Institute at the University of Oxford:
"Already, there are a lot of impacts of anthropogenic climate change in every region around the world ... There are things that we can stop from getting worse by keeping to the targets, but there are a lot of changes which are already here."
Helene Hewitt, a coordinating IPCC lead author and Ocean Modelling group leader at the UK Met Office's Hadley Centre:
"Previous reports may have slightly underestimated the trend of Arctic sea ice (melting) in the past and now we are combining multiple lines of evidence which suggest that we might see a practically sea-ice-free Arctic for the first time by 2050 under all scenarios."
Kristina Dahl, a senior climate scientist at the Union of Concerned Scientists:
"While this report underscores the urgent need for climate action, prior IPCC reports and countless other studies, as well as our lived experience, have already given us more than enough evidence to know that we're in the midst of a crisis brought to us largely by the fossil fuel industry and their political allies."
Helen Mountford, Vice President of Climate and Economics, World Resources Institute:
"If this IPCC report doesn't shock you into action, it should. The report paints a very sobering picture of the unforgiving, unimaginable world we have in store if our addiction to burning fossil fuels and destroying forests continues."
Kaisa Kosonen, Senior Political Advisor on Climate and Energy, Greenpeace:
"We're not going to let this report be shelved by further inaction. Instead, we'll be taking it with us to the courts. By strengthening the scientific evidence between human emissions and extreme weather, the IPCC has provided new, powerful means for everyone everywhere to hold the fossil fuel industry and governments directly responsible for the climate emergency."
Nafkote Dabi, Climate Policy Lead at Oxfam:
"Amid a world in parts burning, in parts drowning and in parts starving, the IPCC today tables the most compelling wake-up call yet for global industry to switch from oil, gas and coal to renewables. Governments must use law to compel this urgent change. Citizens must use their own political power and behaviors to push big polluting corporations and governments in the right direction. There is no Plan B."
Teresa Anderson, climate policy coordinator at ActionAid International:
"The IPCC tells us that limiting average global warming to 1.5C is going to be difficult – but not impossible. This new report drills home the message that radical and transformative action is urgently needed to bring emissions down to real zero. Unfortunately, too many 'net zero' climate plans are being used to greenwash pollution and business-as-usual, jeopardising the goals of the Paris Agreement."
COMPANIES AND INDUSTRIES
Wai-Shin Chan, Global Head of ESG (Environmental, Social and Governance) Research at HSBC:
"The science is crystal clear but the response is not. Investors must use their influence to push decision makers to make the bold emission reductions required to limit the most severe consequences of climate change."