Thursday, February 07, 2019

Climate Change: Breaching the threshold

Last year the IPCC warned us that the Paris Agreement target of limiting climate change to no more than 1.5 degrees above pre-industrial levels was a line in the sand for our species and that if we miss it, we will face catastrophe. Today, the UK Met Office is warning that we could breach that target for the first time within the next five years:

Global warming could temporarily hit 1.5C above pre-industrial levels for the first time between now and 2023, according to a long-term forecast by the Met Office.

Meteorologists said there was a 10% chance of a year in which the average temperature rise exceeds 1.5C, which is the lowest of the two Paris agreement targets set for the end of the century.

Until now, the hottest year on record was 2016, when the planet warmed 1.11C above pre-industrial levels, but the long-term trend is upward.

Man-made greenhouse gases in the atmosphere are adding 0.2C of warming each decade but the incline of temperature charts is jagged due to natural variation: hotter El Niño years zig above the average, while cooler La Ninã years zag below.

In the five-year forecast released on Wednesday, the Met Office highlights the first possibility of a natural El Niño combining with global warming to exceed the 1.5C mark.

The Paris target is a long-term average, so a single year above it doesn't mean disaster. But it would be a foretaste of things to come, and a warning that we need to radically change direction. And if we don't do that, things are going to get pretty unpleasant.