Science Matters

Climate disaster is upon us

Boyce Rensberger

(11/2024) An international team of climate scientists has published one of the most alarming reports on the subject that I’ve read. It is well written, and I think you would appreciate the actual wording of their (long) summary. So here it is, shorn of bibliographic references, which you may find in the original, cited below:

"We are on the brink of an irreversible climate disaster. This is a global emergency beyond any doubt. Much of the very fabric of life on Earth is imperiled. We are stepping into a critical and unpredictable new phase of the climate crisis.

"For many years, scientists, including a group of more than 15,000, have sounded the alarm about the impending dangers of climate change driven by increasing greenhouse gas emissions and ecosystem change. For half a century, global warming has been correctly predicted even before it was observed—and not only by independent academic scientists but also by fossil fuel companies.

"Despite these warnings, we are still moving in the wrong direction; fossil fuel emissions have increased to an all-time high, the 3 hottest days ever occurred in July of 2024, and current policies have us on track for approximately 2.7 degrees Celsius [4.8 degrees Fahrenheit] peak warming by 2100.

"Tragically, we are failing to avoid serious impacts, and we can now only hope to limit the extent of the damage. We are witnessing the grim reality of the forecasts as climate impacts escalate, bringing forth scenes of unprecedented disasters around the world and human and nonhuman suffering. We find ourselves amid an abrupt climate upheaval, a dire situation never before encountered in the annals of human existence. We have now brought the planet into climatic conditions never witnessed by us or our prehistoric relatives within our genus, Homo.

"Last year, we witnessed record-breaking sea surface temperatures, the hottest Northern Hemisphere extratropical summer in 2000 years, and the breaking of many other climate records. Moreover, we will see much more extreme weather in the coming years.

"Human-caused carbon dioxide emissions and other greenhouse gases are the primary drivers of climate change. As of 2022, global fossil fuel combustion and industrial processes account for approximately 90 percent of these emissions, whereas land-use change, primarily deforestation, accounts for approximately 10 percent.

"Our aim in the present article is to communicate directly to researchers, policymakers, and the public. As scientists and academics, we feel it is our moral duty and that of our institutions to alert humanity to the growing threats that we face as clearly as possible and to show leadership in addressing them. In this report, we analyze the latest trends in a wide array of planetary vital signs. We also review notable recent climate-related disasters, spotlight important climate-related topics, and discuss needed policy interventions. This report is part of our series of concise annual updates on the state of the climate."

The 14 authors are at major research universities in eight countries—United States, Germany, United Kingdom, Australia, China, Denmark, Brazil, and Switzerland. The full report was published in the October 8 issue of the journal BioScience. It includes graphs displaying data from 35 planetary "vital signs" that the group tracks annually. Of those, 25 are now at record levels. The other ten are at bad levels but not breaking records at the moment.

One of the record highs is the burning of fossil fuels. We are burning more fossil fuels than ever. Think about that; the world has not cut back even the tiniest bit.

If you would like to read the whole article, it’s on the web. The easiest way to find it is by searching for "the 2024 state of the climate report."

The authors name several actions they think societies and governments should be doing to minimize the harms to come. They conclude with this:

"The surge in yearly climate disasters shows we are in a major crisis with worse to come if we continue with business as usual. Today, more than ever, our actions matter for the stable climate system that has supported us for thousands of years. Humanity's future depends on our creativity, moral fiber, and perseverance. We must urgently reduce ecological overshoot and pursue immediate large-scale climate change mitigation and adaptation to limit near-term damage. Only through decisive action can we safeguard the natural world, avert profound human suffering, and ensure that future generations inherit the livable world they deserve. The future of humanity hangs in the balance."

Some people will find this report alarmist. It is alarming.

Here is what I feel is a non-alarmist note about research into one climate phenomenon, the surprisingly sudden increase in Earth’s average temperature during 2023. It sent climatologists into puzzlement. On a global scale that was the hottest year ever recorded, a whopping increase of one half of a Fahrenheit degree over the year before. The more familiar pace of global warming is more like one-tenth of a degree per year.

James Hanson, the scientist who rang alarm bells about global warming in the 1980s, said our planet had entered a more ominous phase caused by the reduction in particulate air pollution that had been shading the ground. Others suggested their science had a "knowledge gap" about some unknown kind of feedback loop that was not accounted for in computer climate models.

Now scientists have linked the sudden warming to a more familiar process—the shifting flows of surface waters in the tropical Pacific known as El NiZo and La NiZa. From 2020 through 2022, the Pacific was in La NiZa phase, with strong trade winds pushing warm surface water westward from South America toward Indonesia. That pulled up masses of deep, cold water in the eastern Pacific, helping to cool the planet. During El NiZo, the winds die down, and warm water sloshes back toward South America, shutting off the oceanic air conditioner.

Researchers from the University of Miami and Princeton University carried out computer simulations of what happens after La NiZas of varying duration. Their peer-reviewed report was published in the journal Atmospheric Chemistry and Physics.

Here’s what they found: If they modeled one normal La NiZa year, the likelihood of half-degree jumps in temperature the following year was a mere 1.6 percent of the time. But if the computer version of La NiZa lasted three years, as the real one did, the chance of a half-degree warming the following year was 10.3 percent, high enough to make it plausible that the sudden jump seen last year could be explained by the knowledge already built into computer models. No unknown phenomenon is necessarily lurking beyond what scientists already know.

But, I note, that modeling left a 90 percent chance that the sudden warming was caused by something unknown.

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