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For 13 consecutive months, global average air and ocean temperatures were possibly the highest in human history.
This streak of exceptional heat ended last month, as July 2024 was the second-hottest month ever recorded – 0.04 degrees Celsius colder than the previous July on record, the European Union’s Copernicus Climate Change Service reported.
As a result, thousands of people are suffering heat-related deaths, ecosystems are becoming sick, and the planet is on the verge of complete climate change.
“Global temperature rise has consistently broken global average temperature records in recent decades, but it is not common for several months to break them by as much as a quarter of a degree,” says Christopher Merchant, Professor of Ocean and Earth Observation at the University of Reading.
Air temperatures will peak in December 2023, when the Earth will be 1.78 degrees Celsius warmer than the pre-industrial average for that time. The buoy-based sensors confirmed that the ocean was also record-warm at that time.
So what caused this period of unusually high temperatures on land and sea?
“Many factors came together,” Merchant says. “But the biggest and most important is climate change, which is caused primarily by the burning of fossil fuels.”
Big oil and little boy
When scientists refer to the Earth’s pre-industrial temperature, they usually mean the global average taken between 1850 and 1900. Factories and power plants still existed in the late 19th century, especially in Europe and North America, but most of the greenhouse gas emissions generated by human activities had not yet been emitted. In addition, meteorologists have a fairly good temperature record for this period with which to compare modern warming.
This comparison tells us that July 2024 was 1.48 degrees Celsius warmer than a normal July before the massive burning of coal, oil and gas, Merchant says. About 1.3 degrees Celsius of this warming is directly due to global warming caused by these fossil emissions and land-use changes (deforestation, animal husbandry).
The rest, which will cause sudden increases in temperatures starting in June 2023, is largely the result of a natural cycle in the climate known as El Niño.
“The El Niño event is a reorganization of water across a vast area of the Pacific Ocean,” Merchant explains. “El Niño is very important to the functioning of climate around the world because it increases air temperatures, on average, not only in the Pacific Ocean but across the entire Earth’s surface.”
El Niño is over, and so is the record for global average temperatures. Merchant expects temperatures to cool slightly, but says a return to pre-2023 normals is unlikely.
“One likely scenario is that global temperatures will fluctuate at the 1.4°C level for many years, until the next major El Niño event pushes the world above 1.5°C, possibly in the early 2030s,” he says.
Finished? Shoot!
Since the 2015 Paris Agreement, the political consensus on climate change has been to try to limit warming to 1.5 degrees Celsius. A series of catastrophic and potentially irreversible changes to the systems that keep Earth habitable are more likely to occur when this long-term average is exceeded.
It’s possible that this process has already begun for one system in particular: tropical coral reefs. Earth’s largest, the Great Barrier Reef near Australia, has suffered mass bleaching events five times in the past nine summers and recently suffered its worst summer in at least 400 years.
If a new plan exists among the world’s governments (approving new oil and gas production is still a common feature of governance), it seems likely that it would tolerate breaches of the 1.5°C target, at least temporarily.
Jonathan Simmons, a lecturer in international relations at Macquarie University, asks: “The question is how do we manage this period of ‘overshoot’ and bring the temperature back down?”
In autumn last year, a commission made up of former government ministers from several countries published a report on the impacts of temperature rises above 1.5 degrees Celsius. The report argued that high-emitting countries such as Australia should now aim for “net-negative emissions” and immediately begin removing carbon from the air by restoring habitats and deploying carbon capture and storage technology.
Simons summarized its objections to both: “The Commission is concerned that many carbon removal methods are futile, unsustainable or have adverse social and environmental impacts.”
One drastic option that the Climate Overshoot Commission rejected was “solar radiation management”: reflecting some of the sun’s heat and light back into space by injecting reflective particles into the atmosphere, among other techniques. Debate continues among academics as to whether this is now an obnoxious necessity or more reckless vandalism of the atmosphere.
In lieu of radical change, current global climate policy could exceed the 1.5°C target by a degree Celsius or more, according to an analysis published Monday in Nature Climate Change.
The world seems to be delaying the end of fossil fuels, thinking that nature will hold its breath. Research has so far refuted this wishful thinking: computer models predict “extinction waves” and ecological damage spanning centuries from even a short pause at 2°C.
Jack Marley is environment + energy editor at The Conversation UK. This article is republished from here Conversation,
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