Yes, the world is hotter than it has been in 2,000 years or so

A scientific study of tree rings confirms global warming is for real

- FAYE D. FLAM

t's one thing to say the northern hemisphere summer of 2023 was the hottest in 150 years of mercury measurement.

This claim is often dismissed by sceptics of global warming who point out that the Earth has a long history of temperature fluctuations. That's why it's important that a new paper shows last summer was actually the hottest in the last 2,000 yearsand that our current temperatures are even more of an outlier than we realized.

[The question is] whether our recent warming is a major shift or a blip. Thankfully, tree rings hold records that go back thousands of years. In a paper published in Nature, scientists used tree rings to plot summer heat in the northern hemisphere over the past two millennia. 2023 was the hottest of them all. The next hottest 25 have all occurred since 1996. The next runner-up was way back in 246 CE.

What we know of global warming has been changed dramatically by long-term trends revealed by tree rings, ice cores, sediment layers and other such monitors.

In 1998, scientists published a hockey stick graph' of the last 600 years. It showed that global temperatures rose and fell like gently rolling hills until the mid-20th century, when they suddenly soared.