The newest climate report from the Intergovernmental Panel on Climate Change (IPCC) says that climate change was "unequivocally" caused by humans and warns that global temperatures are expected to reach a significant warming milestone in the next 20 years.
The planet is expected to reach average temperatures that are 1.5 degrees warmer than a pre-industrial baseline by 2040, according to summaries provided to reporters in advance of the release of the first part of the report on Monday.
A prior special report from the IPCC has found that keeping warming below this level would prevent climate-related impacts on extreme weather, biodiversity and food security.
The report also warns that climate change will increasingly be seen in heat waves, more frequent and intense precipitation and droughts.
The summary from the IPCC, which was created by the World Meteorological Organization and the United Nations, stated that increases in greenhouse gas concentrations in the atmosphere since about 1750 were “unequivocally caused by human activities.”
It said that it’s likely that humans have already caused about 1.07 degrees Celsius of extra warming compared to pre-industrial temperatures between 1850 and 1900.
Over the next 20 years, averaged out temperatures are expected to exceed 1.5 degrees Celsius of warming.
The new report also found that without serious greenhouse gas emissions reductions, global temperatures will rise by a full 2 degrees Celsius.
It said that if greenhouse gas emissions remain around their current levels in the middle of the century, it’s extremely likely that the planet would exceed two degrees Celsius of warming by 2100, but this level of warming is unlikely to be exceeded if the world reaches net-zero emissions around or after 2050 and has net-negative emissions thereafter.
To reach net-negative emissions, the world would need to be absorbing or removing more greenhouse gases from the air than it's emitting into the air.
The report said that while 1.5 degrees Celsius was more likely than not to be reached, even in a low-emissions scenario, surface temperatures may decline back to below this level by the end of the century if net-zero is reached and is followed by net-negative emissions.
In a scenario where emissions continue at the same level they’re at until the middle of the century, the planet is expected to reach by about 1.5 degrees of warming in the near-term, 2 degrees in the mid-term and 2.7 degrees by the end of the century.
“This report is a reality check,” IPCC Working Group I Co-Chair Valérie Masson-Delmotte said in a statement.
“We now have a much clearer picture of the past, present and future climate, which is essential for understanding where we are headed, what can be done, and how we can prepare,” Masson-Delmotte added.
The report also warns of serious climate change impacts, saying that for each additional one-half degree Celsius of global warming, there will be “clearly discernible” increases in intensity and frequency of hot extremes like heat waves, heavy precipitation and agricultural and ecological droughts.
It said the extremely hot weather resulting from climate change was very likely, and that droughts and fluctuations in precipitation could be projected with high confidence.
It said that worldwide, daily precipitation events would intensify by about 7 percent for each degree Celsius of warming. It also said the share of hurricanes that are in the most intense categories — categories 4 and 5 — are expected to increase with global warming, as are peak wind speeds.
Increased warming is also expected to worsen permafrost thawing and lack of sea ice. The report predicted that at least one September before 2050 will see the Arctic with practically no sea ice and that this is expected to happen more frequently at higher warming levels.
The report also projected the average sea level around the world would rise during the 21st century.
By 2100, levels could rise between .28 and .62 meters under net-zero scenarios, between 0.44 and 0.76 meters if emissions stay where they are until mid-century and rising between 0.63 and 1.01 meters in a “very high” emissions scenario.
“Climate change is already affecting every region on Earth, in multiple ways. The changes we experience will increase with additional warming,” said IPCC Working Group I Co-Chair Panmao Zhai in a statement.
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August 09, 2021 at 03:00PM
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