Limiting global warming to close to 1.5 C or even 2 C over pre-industrial levels will be "beyond reach" without "immediate, rapid and large-scale reductions" in greenhouse gas emissions, the UN's Intergovernmental Panel on Climate Change said in a report on Aug. 9.
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The IPCC report, "Climate Change 2021: The Physical Science Basis," said the global temperature increase was expected to reach 1.5 C over pre-industrial levels in the next 20 years, and showed that greenhouse gas emissions from human activities were already responsible for around 1.1 C of warming since 1850-1900.
"For 1.5 C of global warming, there will be increasing heat waves, longer warm seasons and shorter cold seasons," the report said. "At 2 C of global warming, heat extremes would more often reach critical tolerance thresholds for agriculture and health."
The IPCC said that a pathway to limiting global warming to below 1.5 C was still available, with massive cuts to CO2, methane and other greenhouse gas emissions needed in this decade and beyond.
"This report is a reality check," IPCC Working Group I Co-Chair Valerie Masson-Delmotte said.
"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 said.
The planet was already feeling the effects of human-caused climate change, with stronger evidence of heatwaves, heavy precipitation, droughts and tropical cyclones, the report said.
"Climate change is a problem that is here now," the UN's Environment Programme Executive Director Inger Andersen said at a press conference to launch the report, referencing recent wildfires in Southern Europe and California, flooding in Central Europe and China and more severe storms.
However, the worst of the impacts could be avoided or slowed with rapid, deep and sustained reductions in emissions, the report said.
Extreme weather is already affecting commodity markets globally, S&P Global Platts Analytics said on Aug. 6.
"Weather effects across the world continue to have unexpected impact on commodities," Platts Analytics said in a report. "High temperatures in the US, Korea and Japan have resulted in unprecedented cooling demand."
"The associated forest fires have impacted infrastructure but also created an unexpected boost to jet/kerosene demand for planes to tackle the fires," Platts Analytics said.
"Droughts are impacting crops but also hydroelectricity stocks while in other regions floods impact production. In agriculture, ethanol blend margins have turned positive in the US as rains revive the crops, but in Brazil the third frost has damaged cane yields cutting supply of ethanol and thus supporting stronger gasoline demand."
Heating locked in
The IPCC report said global temperatures would continue to rise until at least mid-century under all scenarios, and temperature increases will surpass 1.5 C and 2 C this century without deep greenhouse gas emissions reductions.
"Climate change is already affecting every region on Earth, in multiple ways," IPCC Working Group I Co-Chair Panmao Zhai said. "The changes we experience will increase with additional warming."
"Stabilizing the climate will require strong, rapid, and sustained reductions in greenhouse gas emissions, and reaching net zero CO2 emissions," Zhai added. "Limiting other greenhouse gases and air pollutants, especially methane, could have benefits both for health and the climate."
The report is a summary of peer-reviewed scientific literature over the last eight years, and contributes to the IPCC's Sixth Assessment Report, which will be finalized in 2022.
While the findings are not new, the report gives a more detailed breakdown of climate change causes and impacts, both globally and at a regional level.
Changing water cycles
In addition to warnings on temperature rises, the report highlighted the risks to changes in the water cycle. Higher global temperatures will bring more intense rainfall and flooding, as well as more intense droughts in some regions, the IPCC said. Extreme rainfall events are expected to intensify by 7% for each 1 C of global warming, it said.
Seasonal snow and ice cover will also decline, the IPCC said, with further warming amplifying the thawing of permafrost, melting of glaciers and the loss of summer Arctic sea ice.
The report warned that a 2-meter rise in sea levels by 2100 could not be ruled out, while the likely rise in sea levels under the very low greenhouse gas emissions scenario was still 0.28-0.55 meters.
The IPCC report also highlighted the risk of increased heat in urban areas as global temperatures rise.
IPCC chair Hoesung Lee said the report was a timely toolbox for negotiators at the COP26 climate talks in November.