New climate change report is ‘code red for humanity’, UN chief warns

Humanity’s negative impact on the climate is “unequivocal and indisputable”, say UN scientists in a new study out today.

They warn that ongoing emissions of damaging greenhouse gases could see a key temperature limit broken in just over a decade.

The IPCC’s document confidently states that “it is unequivocal that human influence has warmed the atmosphere, oceans and land”.

UN Secretary-General António Guterres described the report as “a code red for humanity”.

“If we combine forces now, we can avert climate catastrophe. But, as today's report makes clear, there is no time for delay and no room for excuses. I count on government leaders and all stakeholders to ensure COP26 is a success,” he said.

According to Prof. Ed Hawkins, from the University of Reading, UK, and one of the report's authors, the scientists cannot be any clearer on this point.

“It is a statement of fact, we cannot be any more certain; it is unequivocal and indisputable that humans are warming the planet,” he said.

The authors also show that a rise in sea levels approaching 2m by the end of this century “cannot be ruled out”.

But they also express hope that deep cuts in emissions of greenhouse gases could stabilise rising temperatures.

This assessment from the Intergovernmental Panel on Climate Change (IPCC) features in a 42-page document known as the Summary for Policymakers.

It leads a series of reports that will be published over coming months and is the first major review of the science of climate change since 2013. Its release comes less than three months before a key climate summit in Glasgow known as COP26.

The authors say that since 1970, global surface temperatures have risen faster than in any other 50-year period over the past 2,000 years.

This warming is “already affecting many weather and climate extremes in every region across the globe”.

Whether it's heatwaves like the ones recently experienced in Greece and western North America, or floods like those in Germany and China, “their attribution to human influence has strengthened” over the past decade.

The new report also makes clear that the warming experienced to date has made changes to many of the planetary support systems that are irreversible on timescales of centuries to millennia.

The oceans will continue to warm and become more acidic. Mountain and polar glaciers will continue melting for decades or centuries.

“The consequences will continue to get worse for every bit of warming,” Prof. Hawkins said. “And for many of these consequences, there's no going back.”

In 2015, almost every nation on Earth signed up to the goals of the Paris climate agreement that aims to keep the rise in global temperatures well below 2C this century and to pursue efforts to keep it under 1.5C.

This new report says that under all the emissions scenarios considered by the scientists, both targets will be broken this century unless huge cuts in carbon take place.

The authors believe that 1.5C will be reached by 2040 in all scenarios and if emissions aren't slashed in the next few years, this will happen even earlier.

The consequences of going past 1.5C over a period of years would be unwelcome in a world that has already experienced a rapid uptick in extreme events with a temperature rise since pre-industrial times of 1.1C.

“We will see even more intense and more frequent heatwaves,” Dr Friederike Otto from the University of Oxford, UK, and one of the IPCC report's authors, said.