The 2015 Paris Agreement, meant to constrain global warming to 1.5 degrees Celsius above pre-industrial levels, has already been breached, according to European scientists who found that last summer was Earth 's hottest in the past 2,000 years across the Northern Hemisphere.

Based on an analysis of ancient tree rings that date all the way back to the year 1, last summer was the hottest in the past 2,000 years.

That data already had confirmed the summer of 2023 as the hottest ever recorded. However, the Cambridge crew turned to tree ring data to reach back 2,000 years and last summer was still the hottest over that entire period of time.