Image copyright EPA Image caption The UN released the report before negotiators at the UN climate change conference in Poland
A report by nearly 100 senior UN and U.S. officials urges global leaders to urgently and comprehensively cut greenhouse gas emissions to avoid the worst impacts of climate change.
It is the most definitive assessment of the scale of climate change to date and an argument that plans in place won’t even meet a less dire set of targets.
A version of the study was presented ahead of the United Nations climate conference (COP24) in Poland.
Negotiators will meet to work on a range of climate change measures, including the details of an international agreement to curb carbon emissions that will replace the current UN framework.
Ahead of the conference, U.S. Secretary of State Mike Pompeo, leading the U.S delegation, said the government would not have “one iota of interest” in a plan to limit global warming to no more than 1.5C above pre-industrial levels.
The degree of detail in the U.S report – the most comprehensive synthesis to date – will likely hurt the country’s reputation.
Image copyright EPA Image caption The focus of the report is on the potential impact of climate change over the coming decades
It doesn’t just look at how much human activity is contributing to global warming, but explores the long-term consequences for almost every aspect of life on Earth.
It paints a grim picture of runaway global warming, brought on by factors including cooling oceans, rising seas and increased extreme weather events that could displace hundreds of millions of people.
“We can and must reduce emissions at an even faster pace, without compromising on the world’s ability to adapt to the risks of climate change and keep the temperature rise within 1.5°C,” said Noah Diffenbaugh, a co-author of the report and a senior fellow at Stanford University’s School of Earth, Energy & Environmental Sciences.
“That’s what we will be talking about at COP24.”
Dozens of cabinet secretaries, former heads of state and US lawmakers were involved in the reports for the Trump administration.
Briefing reporters before the release, a State Department official said the report outlines a range of options for cutting carbon emissions in the United States and around the world, based on a simulation of trends throughout the coming century.
The choice of scenarios range from the lowest – 2C – to the highest – 3C – which the official said would have catastrophic consequences.
Image copyright EPA Image caption The report stresses that while the implications for climate change are concerning, the world can prepare to protect against the worst impacts
Despite what happened over the past year – namely President Donald Trump pulling the United States out of the Paris climate agreement and cancelling the administration’s contribution to the Green Climate Fund – officials say the report wasn’t prompted by any external pressure.
“The report is just about a year old and we were encouraged by the encouragement that was taken by many international parties and were as we brought the report to them, we also asked them if we could have more time to consider the consequences of some of the policy shifts in the United States,” said one official.
“They said yes, give us a little more time and we are grateful to the host, Poland, for allowing us to do that,” the official added.
Although the study concludes climate change is occurring, its findings suggest by mid-century it will intensify the impact on some areas. But not all regions.
Read a summary of the report on BBC News