Global warming exceeds the 1.5 degree target for the first time

For the first time ever, we have seen global temperatures to be over 1.5 degrees Celsius warmer than pre-industrial levels, with an average rise of 1.52 degrees.

This warming target was agreed on as part of the Paris Agreement in 2015, signed by 196 parties. It represents a key target for fighting against climate change, so its breach would be catastrophic. Whilst it is only officially breached once temperatures have exceeded 1.5 degrees of warming for 20 successive years, this year-long pattern shows we are well on track. European climate monitors say we should take this as a “warning to humanity”.

The temperature rise is caused by a combination of anthropogenic damage, such as burning fossil fuels, and the natural El Niño events, whereby a weakening of the usual westward-blowing trade winds causes warmer surface waters to move from the western to eastern Pacific. It is hoped that as El Niño events subside in the next few months, temperatures will stabilise below 1.5 degrees of warming.

However, recent analysis of 300 year old marine sponges reveal that we may have actually exceeded 1.5 degrees of warming much earlier than we thought. The IPCC uses global temperatures from 1850-1900 as a baseline against which we measure current warming, but a team at the University of West Australia Oceans Institute advocates for us changing these baselines. By analysing the ratio of strontium to calcium in the skeletons of marine sponges, we are able to get an accurate proxy for global temperature as far back as 300 years, and this paints a very different picture.

“We have an alternate record of global warming… It looks like temperatures were underestimated by about half a degree.”

Malcolm McCulloch, leader of research team

Nonetheless, this year-long breach is not the only milestone we have reached recently, the second being a lot more positive. COP28 marks the first time ever that fossil fuels have been mentioned in the final legislation from a COP agreement, with a landmark deal to “transition away” from their use. This represents fundamental recognition of the damage that fossil fuels are having on our climate.  

By combining efforts of reduced greenhouse gas emissions with more negative emission technology such as carbon capture and storage and reforestation, scientists urge that we are still able to curb our warming to avoid catastrophe. “Doom is not inevitable”, states Zeke Hausfather, a climate scientist at Berkeley Earth, we just simply need to recognise this as the wake up call that it is.

Image credit: Nicola via Unsplash

Image description: Protest sign saying “There’s no planet B”