Harv's Corner 06/30/2025

Harv's Corner

Ignoring global warming is profoundly dangerous, as it accelerates the accumulation of greenhouse gases, resulting in more frequent and intense heat waves, droughts, and storms. This escalating climate disruption threatens global food and water supplies, causes catastrophic sea-level rise that endangers coastal communities, and triggers widespread ecosystem collapse, jeopardizing the stability of human civilization and the natural world.

​CLIMATE DECLINE IS SPEEDING UP
Release of greenhouse gas nears key limit.

By SETH BORENSTEIN • The Associated Press

​WASHINGTON - Humans are on track to release so much greenhouse gas in less than three years that a key threshold for limiting global warming will be nearly unavoidable, according to a study scheduled for release on Thursday.

The report predicts that society will have emitted enough carbon dioxide by early 2028, making it more likely than not that crossing an important long-term temperature boundary will occur. The scientists calculate that by that point, there will be enough of the heat-trapping gas in the atmosphere to create a 50-50 chance or greater that the world will be locked into 1.5 degrees Celsius (2.7 degrees Fahrenheit) of long-term warming since preindustrial times. That level of gas accumulation, which comes from the burning of fuels such as gasoline, oil, and coal, is sooner than the same group of 60 international scientists calculated in a study last year.

"Things aren't just getting worse. They're getting worse faster," said study co-author Zeke Hausfather of the tech firm Stripe and the climate monitoring group Berkeley Earth. "We're actively moving in the wrong direction in a critical period of time that we would need to meet our most ambitious climate goals. In some reports, there's a silver lining. I don't think there really is one in this one."

The 1.5 degrees Celsius goal, first set in the 2015 Paris Agreement, has been a cornerstone of international efforts to curb the worsening effects of climate change. Scientists say that crossing this limit would mean worse heatwaves and droughts, bigger storms, and sea-level rise that could imperil small island nations. Over the last 150 years, scientists have established a direct correlation between the release of specific levels of carbon dioxide, along with other greenhouse gases such as methane, and corresponding increases in global temperatures.

In Thursday's Indicators of Global Climate Change report, researchers calculated that society can spew only 143 billion more tons of carbon dioxide before the 1.5 limit becomes technically inevitable. The world is producing 46 billion tons a year, so the inevitability should occur around February 2028, as the report is measured from the start of this year, the scientists wrote. The world now stands at approximately 1.24 degrees Celsius (2.23 degrees Fahrenheit) of long-term warming since pre-industrial times, the report stated.

Earth's energy imbalance
The report, published in the journal Earth System Science Data, shows that the rate of human-caused warming per decade has increased to nearly half a degree (0.27 degrees Celsius) per decade, according to Hausfather. And the imbalance between the heat Earth absorbs from the sun and the amount it radiates out to space, a key climate change signal, is accelerating, the report said.
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"It's quite a depressing picture, unfortunately, where if you look across the indicators, we find that records are really being broken everywhere," said lead author Piers Forster, director of the Priestley Centre for Climate Futures at the University of Leeds in England. "I can't conceive of a situation where we can really avoid passing 1.5 degrees of very long-term temperature change."

The increase in emissions from burning fossil fuels is the main driver. However, reduced particle pollution, which includes soot and smog, is another factor because those particles have a cooling effect that masks even more warming from appearing, scientists said. Changes in clouds also factor in. That all shows up in Earth's energy imbalance, which is now 25% higher than it was just a decade or so ago, Forster said.

Earth's energy imbalance "is the most important measure of the amount of heat being trapped in the system," Hausfather said. The Earth continues to absorb more heat than it releases. "It is very clearly accelerating. It's worrisome," he said.

Crossing the temperature limit
The planet temporarily passed the key 1.5 limit last year. The world experienced 1.52 degrees Celsius (2.74 degrees Fahrenheit) of warming since preindustrial times for an entire year in 2024, but the Paris threshold is intended to be measured over a longer period, typically 20 years. Still, the globe could reach that long-term threshold in the next few years, even if individual years haven't consistently hit that mark, due to how the Earth's carbon cycle works.

That 1.5 is "a clear limit, a political limit for which countries have decided that beyond which the impact of climate change would be unacceptable to their societies," said study co-author Joeri Rogelj, a climate scientist at Imperial College London.

The mark is so important because once it is crossed, many small island nations could eventually disappear because of sea level rise, and scientific evidence shows that the impacts become particularly extreme beyond that level, especially hurting poor and vulnerable populations, he said. He added that efforts to curb emissions and the effects of climate change must continue even if the 1.5-degree threshold is exceeded.

Crossing the threshold "means increasingly more frequent and severe climate extremes of the type we are now seeing all too often in the U.S. and around the world — unprecedented heat waves, extreme hot drought, extreme rainfall events, and bigger storms," said University of Michigan environment school dean Jonathan Overpeck, who wasn't part of the study.

Andrew Dessler, a Texas A&M University climate scientist who wasn't part of the study, said the 1.5 °C goal was aspirational and not realistic, so people shouldn't focus on that particular threshold.
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"Missing it does not mean the end of the world," Dessler said in an email, though he agreed that "each tenth of a degree of warming will bring increasingly worse impacts."