Planet Earth

A tab about learning to live within Gaia, the miraculous web of life embracing Planet Earth. So far mostly about global warming.

Latest on global temperature (Jan 2022)

The state of global warming is not well conveyed by words. The media routinely confuse and minimise it anyway, through their simplistic application of ‘balance’: a knowledgable scientists is ‘ balanced’ by an ignorant denialist. That is on top of a widespread bias born of self interest and an unwillingness to face the real situation – which is also denial.

I therefore reproduce here an up-to-date graph of mean global temperature. It is from James Hansen and Makiko Sato of Columbia University. You can see recent years have been distinctly hotter than the past, hotter even than the trend from 1970 to 2010.

Remember when there was supposed to have been a pause in global warming? Deniers who made that claim started their plot with 1998, and up until 2012 the temperature wobbled around without getting much higher. That was obviously an incorrect interpretation even at the time, because it overlooked the years just before and after 1998. Looking at the whole graph you can see that 1998 was well above the trend, 1999 and 2000 were well below, and the temperatures wobbled around the trend (the green line) through the following decade. There never was a pause, it was an artefact of cherry picking the data: starting the graph at a high outlier to make the following points look similar. The 11-year (132-month) running mean in red shows a steady warming trend.

1998 was a year of a very strong El Niño condition in the Pacific, in fact the strongest known until then, and El Niños always bump the global mean up a little bit. The opposite condition, La Niña occurred around 2010 and kept the temperatures below trend. The worry was what might happen when La Niña ceased.

We soon found out. In the three years after 2013 we experienced the largest and most rapid increase in the whole record, from 0.97 to 1.3°C. (The 2014 datum is partly obscured by the green line.)

The politicians claim their policies will keep warming below 1.5°C, and definitely below 2°C. There are two problems with that. First, their collective commitments so far are only enough to keep warming below about 3°C. The other is that there is inertia in the system: it would take 2-3 decades for warming to slow and reverse.

It’s true the temperature dropped after its 2016 peak, but it only came down to the green trend line. Then it rose again nearly as high. If the trend still applied, it should go below the trend line. Hansen and Mikako argue that in fact the rate of warming has accelerated since about 2013.

There were three major bleachings of the Great Barrier Reef in 2016, 2017 and 2020. Another is feared this year and it is likely that the temperature will spike even higher after the current La Niña ends. The Reef is already severely damaged.

I wrote in 2017 that based on trends the Great Barrier Reef would be reduced to a pathetic remnant within a decade or so. I updated that briefly in 2019, and the same prognosis still applies. The links to images in the 2017 piece were lost when I changed my web site. I will pick up that topic in a seperate posting.