Summer of 2023 was the hottest in two millennia, says study

A new study analyzing ancient tree rings reveals that last summer was the hottest in the past 2,000 years, with unprecedented warmth across the Northern Hemisphere.

Doyle Rice reports for USA Today.


In short:

  • Tree rings indicate summer 2023 was 4 degrees warmer than the average from 1 to 1890.
  • The study suggests that current warming trends surpass the goals of the 2015 Paris Agreement.
  • High heat fueled severe weather events globally, from wildfires to intense heat waves and heavy rains.

Key quote:

“It’s true that the climate is always changing, but when you look at the long sweep of history, you can see just how dramatic recent global warming is.”

— Jan Esper, lead author, Johannes Gutenberg University

Why this matters:

Such unprecedented heat is a stark reminder of the urgent need to reduce greenhouse gas emissions to mitigate severe health impacts and prevent further climate-related disasters. Read more: Heat, air pollution and climate change … oh my! Was summer 2023 the new normal?


Flags of the EU flying outside a glass and steel building

Hungary's carbon tax violates EU rules, top court says

The European Union's top court says Hungary's tax on CO2 emission allowances, introduced in 2023, is against EU law, as it removes the operators' incentive to invest in measures to cut emissions.

A mountain highway winding through a forest toward mountains in the background
Credit: Hans/Unsplash+

How ‘national security’ became the new justification for drilling

What’s happening to the public lands and oceans we thought were protected?
Two scuba divers looking at coral in the ocean

World's first fossil fuel phase-out conference puts ocean in its sights

Across 11 frontier regions, 19% of Marine Protected Areas are already overlapped by active fossil fuel oil and gas blocks.
A closeup of a jail cell door with lock

Two Indigenous rights advocates remain behind bars in Russia

The UN’s biggest Indigenous gathering is happening next week, but a key climate advocate will be missing.
A shareholder agreement with a gold pen on top of it

The man whom Exxon tried to drill

After years of using shareholder votes to pressure oil giants on climate, one activist triggered a corporate backlash that is reshaping the limits of investor power.
A row of solar panels in the snow with the setting sun in the background

‘A ray of hope’: EU governments gathering to plan way out of fossil fuel reliance

Energy crises could be a thing of the past if reliable, cheap, and abundant clean energy is given precedence over fossil fuels.

Many solar panels arranged in a circular pattern viewed from above

Solar power in Morocco's desert: bold vision, mixed results

A massive solar tower in the Moroccan desert is the beacon of an ambitious push for a clean energy future. But fossil fuels and grid constraints stand in the way.
From our Newsroom
Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

Multiple Houston-area oil and gas facilities that have violated pollution laws are seeking permit renewals

One facility has emitted cancer-causing chemicals into waterways at levels up to 520% higher than legal limits.

Regulators are underestimating health impacts from air pollution: Study

Regulators are underestimating health impacts from air pollution: Study

"The reality is, we are not exposed to one chemical at a time.”

Pennsylvania governor Josh Shapiro speaks with the state flag and American flag behind him.

Two years into his term, has Gov. Shapiro kept his promises to regulate Pennsylvania’s fracking industry?

A new report assesses the administration’s progress and makes new recommendations

silhouette of people holding hands by a lake at sunset

An open letter from EPA staff to the American public

“We cannot stand by and allow this to happen. We need to hold this administration accountable.”

wildfire retardants being sprayed by plane

New evidence links heavy metal pollution with wildfire retardants

“The chemical black box” that blankets wildfire-impacted areas is increasingly under scrutiny.

Stay informed: sign up for The Daily Climate newsletter
Top news on climate impacts, solutions, politics, drivers. Delivered to your inbox week days.