The Intergovernmental Panel on Climate Change (IPCC) released an alarming new report on the state of the climate today, based on 14,000 pieces of scientific literature synthesized by hundreds of experts. It’s a full-throated declaration of what scientists know about how humanity has set the planet on fire: how hot it’s gotten and will get, how much polar ice is melting, how droughts and storms are worsening, and how dire the future looks—unless we take drastic and immediate steps to stop loading the atmosphere with carbon.
The Paris Climate Agreement’s optimistic goal is to limit global average temperatures to 1.5 degrees Celsius above preindustrial levels, while avoiding 2 degrees of warming. According to the new report, the temperature has already risen by 1.1 degrees Celsius and is on track to reach 1.5 degrees Celsius sometime in the early to mid-2030s if nothing changes.
The Arctic, however, is a major source of concern because it is warming at twice the rate of the rest of the planet. According to Isla Myers-Smith, a global change ecologist at the University of Edinburgh who studies the region but was not involved in the IPCC report, it is now three times as fast. The rise can be attributed to a variety of factors, including altered ocean currents and the albedo effect: as more ice melts, it exposes the darker land beneath, which further heats the region, leading to more melting.
According to the IPCC report, between 2011 and 2020, the average size of the area covered by Arctic sea ice was smaller than it had been since at least 1850, and there was less late-summer Arctic sea ice than at any time in the previous 1,000 years.
The report estimates that under the very low emissions scenario, global mean sea level rise could range from one to two feet by the year 2100. However, in a high-emissions scenario, that figure would be six and a half feet by 2050, and more than 16 feet by 2150.
A warming climate would also increase precipitation in some areas, as shown in the maps above, which show how much the annual average would rise compared to the period between 1850 and 1900 if the climate warmed by 1.5, 2 or 4 degrees Celsius. Precipitation would increase significantly over high latitudes, around the equatorial Pacific, and in some areas that already have monsoons.
You might believe that a hotter climate means less rain, but this is not always the case. Hotter temperatures cause more moisture to evaporate from the land, resulting in rain, and a warmer atmosphere retains more moisture. This increased precipitation can be a mixed blessing, as it can lead to more severe floods, such as those that devastated parts of Europe last month.
Despite the fact that we are mistreating the planet, it is doing everything it can to save us. When we burn carbon, a large portion of it is absorbed by the oceans and land—the carbon dioxide is incorporated into the water, while trees breathe in the gas and expel it. Climate change would be far more disastrous if these carbon “sinks” did not exist; the planet will not get us out of this mess; only a dramatic reduction in emissions will.
The report notes that under its very low emissions scenario, the average global surface temperature is very likely to have risen by 1 to 1.8 degrees Celsius between 2081 and 2100. To be sure, this is still dangerous, but it is far preferable to an intermediate level of emissions, which raises the figure to 2.1 to 3.5 degrees. It’s even worse in the very high scenario: 3.3 to 5.7 degrees.