Has the world crossed the 1.5C warming threshold already ?

                                                                                                      Shutterstock

Earlier this week, the media carried a series of articles suggesting that the threshold of limiting increased global temperature to 1.50 C had already been crossed. The articles are based on new research on ocean temperatures that surmised that "hotter land temperatures, together with the earlier onset of industrial-era warming, indicate that global warming was already 1.7 +/- 0.1C above pre-industrial levels by 2020".  In short, this research and possible discovery means that the temperature is 0.5C higher than IPCC estimates with 20  C projected by the late 2020s, nearly two decades earlier than expected.

A team led by Professor Malcolm McCulloch from the University of Western Australia studied 300 years of records preserved in the skeletons of long-lived sea sponges from the Eastern Carribean. Of particular importance the sclerosponge thermometry shows that global warming has already exceeded 1.50 C. The focus of the research was changes in the amount of a chemical known as 'strontium' in the sponges skeletons. The changes in the amount of strontium reflects variations in seawater temperatures over the sponges' life.

The conclusion reached is that the Earth may already have reached at least 1.7C warming since pre-industrial times, well above the Paris Climate target of 1.5C. The opportunity for controlling climate change at the first milestone has already been lost.

Link to Nature article: 300 years of sclerosponge thermometry