There’s a more than 60% chance that the Earth’s temperature will bump up against the warming level that has shaped global climate policy — 1.5 degrees Celsius, or 2.7 degrees Fahrenheit — within the next five years, the United Nations weather organization said Wednesday.
A flirtation with that increase in average temperature would likely be fleeting, driven by a temporary blast of heat from El Niño, a cyclical, naturally occurring weather phenomenon.
But the development is still one to watch, scientists say, because an increase in man-made global warming means that when El Niño layers on its temperature boost, the dangerous implications of potentially extreme heat on human health, agriculture, healthy oceans and more are worsened.
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The World Meteorological Organization forecasts a 66% likelihood that between now and 2027, the globe will log a year that averages 1.5 degrees Celsius warmer than the average temperature in the mid-19th century. That’s the routinely used comparison that tracks the modern industrial age from its beginnings up to current times, as coal, natural gas
— which emit greenhouse gases that warm the atmosphere — continue to power much of modern life.
Average temperatures are then expected to drop back down but to continue on their long-term upward trend, the WMO said in a report.
The 1.5-degree guardrail was set by the voluntary 2015 Paris climate agreement. Since then, more countries have pledged to limit long-term warming to this line, if possible. Steps include converting more energy sources to solar, wind and nuclear and swapping gas vehicles for electric. As 1.5 degrees of warming drives the agenda, scientists have warned that a sustained 2-degree warming could prove catastrophic.
“This report does not mean that we will permanently exceed the 1.5 C level specified in the Paris Agreement which refers to long-term warming over many years. However, WMO is sounding the alarm that we will breach the 1.5 C level on a temporary basis with increasing frequency,” WMO Secretary-General Petteri Taalas said in a statement.
“We haven’t been able to limit the warming so far and we are still moving in the wrong, wrong direction,” Taalas said at a press conference on Wednesday.
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In other recent reports, the UN climate division has suggested that without more aggressive reductions in greenhouse-gas emissions, the planet is on track to warm by an average of 2.1 to 2.9 degrees Celsius over preindustrial levels by 2100.
The chances that a single year will hit the 1.5-degree threshold within five years have increased from 48% last year, 40% the year before, 20% in 2020 and 10% about a decade ago, UN data show. The WMO report is based on calculations collected at 11 climate-science centers across the globe.
The report’s authors say that while they are highlighting the potential for more frequent single-year breaches of the 1.5-degree line, it’s important to remember that one year’s weather and temperature events do not typically make a trend. Climate scientists are more concerned with 30-year averages.
Read more of MarketWatch’s Living With Climate Change coverage.