2019 was the second-warmest year ever, just shy of the record set in 2016, says the World Meteorological Organization, closing out the warmest decade (see figure below).
As usual for a warming planet, the heat is concentrated in the poles (see figure below), more in the Arctic and Greenland, melting ice caps over there, rising sea level worldwide.
In December 2019, the average temperature across Australia was about 2°C above what would be expected for the present-day, which is another 1.5°C above temperatures that were normal for December before humans started warming the climate. These extreme temperatures were combined with low rainfall totals — in December the country had the least rainfall on record — the heat has contributed to a severe drought that has gripped most of the country since 2017, leading to the catastrophic bushfires which have devastated large areas, killing millions of living animals and destroying centennial forests..
But, according to the climate scientist Ed Hawkins, what may be considered ‘normal’ is constantly changing.
In a world which has warmed by 3°C – roughly the current global trajectory – what was extreme will be entirely normal.
The extreme temperatures experienced in Australia are therefore a glimpse of the future. Similar unusual weather patterns to those experienced in December in that future world would cause extreme temperatures that are unimaginable now.
The graphic above uses observations of average December temperature for Australia and regresses this against a smoothed global annual average temperature. Land areas warm faster than ocean areas, and so it is found that December temperatures in Australia are warming 1.4x faster than the global annual average. Assuming the same relationship holds in future allows the estimates of what Australian temperatures will be normal for different levels of total global warming.
(Head picture: On January 9, 2020, the Operational Land Imager (OLI) on Landsat 8 acquired natural-color observations of burned land and thick smoke covering Australia’s Kangaroo Island. According to news reports, at least 156,000 hectares (600 square miles, nearly one-third of the land area) have burned and 50 homes have been destroyed on the island of 4,700 people. NASA Earth Observatory images by Lauren Dauphin, using Landsat data from the U.S. Geological Survey. Caption by Mike Carlowicz.)
