How today’s global warming is unlike the last 2,000 years of climate shifts
Previous cooldowns and warm-ups were regional, driven by natural forces, paleoclimate data show
![hot subway](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2019/07/072419_CG_climate_feat.jpg?fit=1030%2C580&ssl=1)
HOT ERA Across 98 percent of Earth, the end of the 20th century saw the hottest temperatures of the last two millennia. Since then, average global temperatures are still increasing, causing record-breaking heat waves such as struck New York City (shown) in mid-July.
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