Jul 25, 2019

Why today's global warming is "unprecedented"

Illustration: Aïda Amer/Axios

Recent global warming is an "unprecedented" worldwide phenomenon that differs from the more regional and staggered climatic variations that occurred during the past 2,000 years, a new study concludes.

Why it matters: The paper in the peer-reviewed journal Nature underscores the scope of human-driven warming and how it contrasts with variations in the pre-industrial era.

Where it stands: The study, using information from tree rings, ice cores and more, reconstructs past periods to show that major fluctuations occurred in different places at different times.

  • The paper finds "no evidence for preindustrial globally coherent cold and warm epochs" over the past 2,000 years.
  • For instance, the "little ice age" was coldest in the eastern and central Pacific Ocean in the 15th century, in northwestern Europe and southeastern North America in the 17th century, and in most other places in the 19th century.

The big picture: The results support a "regional framing" for understanding the climate variability in the 2 millennia before the industrial revolution — and demonstrates that it's a very stark contrast to what's happening now.

"When we go back in the past these are regional phenomena. We found 98% of the globe has this coherent warming during this contemporary period after the Industrial Revolution,"
— said co-author Nathan Steiger of Columbia University at a press briefing this week.

The bottom line: The findings provide "strong evidence that anthropogenic global warming is not only unparalleled in terms of absolute temperatures, but also unprecedented in spatial consistency within the context of the past 2,000 years," the paper states.

What they're saying: University College London scientist Mark Maslin, who was not part of the study, told Reuters the results should "finally stop climate change deniers claiming that the recent observed coherent global warming is part of a natural ... cycle."

Go deeper: All the global temperature records broken in 2019, so far

Go deeper

July 2019 was the hottest month on record

Photo: Samuel Boivin/NurPhoto via Getty Images

July 2019 was confirmed as the hottest month ever recorded, slightly topping or equal to global temperatures in July 2016, according to the European Union's Copernicus Climate Change Service (C3S).

The big picture: Regions around the world have seen unrelenting, record-breaking temperatures this summer, causing dangerous conditions and deaths throughout. Studies have shown that the increase in the frequency of heat waves and the rise in global temperatures is symptomatic of human-caused climate change.

Go deeperArrowAug 5, 2019

July was Earth's hottest recorded month

River Loire at Montjean-sur-Loire, western France on July 24, 2019. Photo: Loic Venance/AFP/Getty Images

This July surpassed August 2016 as the hottest-ever month on record by 0.14 degrees Fahrenheit, the Washington Post's Andrew Freedman reports.

The big picture: Deke Arndt, head of climate monitoring for NOAA, tells the Post that "July 2019 marked the 415th straight month that was warmer than the 20th century average." 9 of the 10 warmest Julys on record have taken place since 2005, and Arctic and Antarctic sea ice fell to their lowest-recorded levels this July, according to NOAA.

Go deeperArrowAug 15, 2019

Historic heat wave shatters all-time temperature records across Europe

A boy attempting to cool off under a public water spray in Paris. Photo: Philippe Lopez/AFP/Getty Images

A blistering heat wave across Europe shattered a number of all-time temperature records across the continent on Thursday.

By the numbers: On Thursday, Paris reached 42.6°C (108.7°F) — by far its hottest temperature on record, according to Météo-France.

Go deeperArrowJul 25, 2019