This year will be one of the three hottest on record for the globe, as marine heat waves swelled over 80 percent of the world’s oceans and triple-digit heat invaded Siberia, one of the planet’s coldest places. These troubling indicators of global warming are laid out in a UN State of the Climate report published Wednesday.
To mark the report’s release and to build momentum toward new climate action under the Paris accord, UN Secretary General António Guterres summarized the findings in unusually stark terms.
’'To put it simply,’' he said in a speech at Columbia University, ’'the state of the planet is broken.’'
’'Dear friends, humanity is waging war on nature. This is suicidal,’' Guterres said. ’'Nature always strikes back, and it is already doing so with growing force and fury.’'
He cited reductions in biodiversity, the bleaching of coral reefs, the fact that the past decade was the hottest in human history, and other indicators to emphasize that time is running out to limit the harms from global warming by reining in greenhouse gas emissions. In addition, Guterres ticked off a slew of extreme weather events that occurred this past year, from Siberian fires to the record active Atlantic hurricane season.
The climate report, which is a product of the World Meteorological Organization and other UN agencies, found that the past six years, including 2020, are likely to be the six warmest on record.
This year is likely to be one of the warmest despite the cooling influence of a La Niña event in the tropical Pacific Ocean, which tends to depress global average temperatures slightly. Instead, the braking influence of a La Niña does not seem to be slowing down the pace of climate change. Global temperature data from five agencies, including NASA and the National Oceanic and Atmospheric Administration, shows that through October, the year-to-date has been running as the second-warmest, behind 2016.
There is a chance that, once additional data through December is incorporated, some agencies will rank 2020 as the warmest year, narrowly beating 2016.
’'Every 10th of a degree of warming matters, and today we are at 1.2 degrees [Celsius] of warming and already witnessing unprecedented climate extremes and volatility, in every region and on every continent,’' Guterres said, comparing global average surface temperatures today to the average from 1850 to 1900.
Petteri Taalas, the secretary general of the WMO, said in a news release that there is at least a one-in-five chance of the global average temperature temporarily exceeding 1.5 degrees Celsius (2.4 Fahrenheit) by 2024.
This would be significant because that is a guardrail established under the Paris agreement, and residents of many low-lying small island states regard it as the threshold beyond which they face an existential risk from sea-level rise.
Guterres said nations need to slash greenhouse gas emissions by at least 6 percent per year through 2030 to have a chance at holding warming to 1.5 degrees above preindustrial levels, but, instead, ’'we’re headed in the opposite direction,’' with increasing global emissions each year. ’'Now we must use 2021 to address our planetary emergency,’' he said.
Parts of the planet are warming much faster than the global average, as has been on display this year.
In the Siberian Arctic, for example, temperatures have been more than 9 degrees Fahrenheit above average for the year. Temperatures were especially warm there in June, when a temperature of 100.4 degrees Fahrenheit was recorded in the town of Verkhoyansk, setting what is likely to be a record for the hottest temperature north of the Arctic Circle. The hot weather in Siberia helped drive the most active wildfire season that area has seen in at least 18 years of record-keeping, which emitted more planet-warming carbon dioxide, methane, and other gases.
The consistently warmer-than-average conditions seen this year in the Siberian Arctic have also raised worries about permafrost melt, which has the potential to release large amounts of greenhouse gases.
The report also notes that ocean heat content continues to set records, which is in line with the fact that the oceans are the biggest absorber of extra heat accumulating as a result of increased greenhouse gases.