In 2013, the IPCC’s assessment concluded that humans were the “dominant cause” of global warming since the 1950s. Its findings spurred the negotiations that led to the 2015 Paris agreement, which compels signatory governments to commit to reforms that will restrict planetary warming this century to under 2 degrees Celsius, and ideally 1.5 degrees Celsius. In the intervening years, the IPCC has issued a number of special reports, including analyses of the state of the oceans and the planet’s frozen corners, land use and phenomena like desertification, and a 2018 red alert over the rapidly narrowing window for governments, civil society and the private sector to push through drastic reforms that could stave off global temperatures rising at an average above 1.5 degrees Celsius.
The conclusions of the latest study — delayed for months by the coronavirus pandemic — are expected to sound an even grimmer warning about the pace of planetary warming. It is likely to offer a projection of how much more emissions can enter the atmosphere before that 1.5-degree threshold is crossed, a point beyond which experts warn of catastrophic events facing the planet. The assessment will also project with greater specificity what some of these disastrous effects may be.
“The report will cover not only the fact that we are smashing record after record in terms of climate change impacts, but show that the world today is in uncharted territory in terms of sea level rise and ice cover,” climate scientist Kelly Levin told Reuters. Levin added that the report “will underscore the urgency for governments to ramp up climate action.”
This was readily apparent even without the IPCC’s conclusions. Extreme weather linked to climate change has wreaked havoc across the globe in recent weeks. After torrential rains led to floods across areas of Northern Europe, wildfires are burning their way through parts of Southern Europe. In Italy, the number of these blazes is estimated to have tripled this year compared with the yearly summer average. In Greece, fires prompted evacuations around the archaeological site of the original home of the Olympics.
In Turkey, scorching temperatures — set to rise 8 degrees Celsius above seasonal norms in some areas — triggered a wave of fires across dozens of its provinces. They burned through more than 100,000 hectares of land and displaced thousands of people, and shut down stretches of the country’s tourist-clogged Aegean coast. Critics of Turkish President Recep Tayyip Erdogan lambasted his government’s lack of preparedness and historic disregard for climate action and environmental protections.
“The discrepancy between the Turkish government’s talk of imperial grandeur and its real capability to deliver basic emergency services to its citizens was glaring,” wrote Asli Aydintasbas in a Washington Post op-ed. “Having long misdirected resources to foreign military adventures and mega infrastructure projects, the government failed to deliver in a time of need.”
Of course, the coming years of increasingly extreme and erratic weather will strain many other governments, too. A summer of brutal heat waves across the Northern Hemisphere is only a sign of things to come, according to various new climate models. “As global temperatures have increased, extreme heat events in the Northern Hemisphere have occurred with greater frequency and intensity,” my colleague Kasha Patel wrote this week. “Deadly, record-crushing heat waves have scorched parts of the United States, Europe and the Arctic in just the past two decades. The World Health Organization reports that more than 160,000 heat-related deaths occurred from 1998 to 2017 globally.”
Meanwhile, we’re still grappling with the real-world, real-time impact of climate change. A heat wave last week in Greenland led to the region’s biggest melting event so far in the 2021 season, with researchers calculating that enough ice seeped into the ocean to cover all of Florida with two inches of water. “It’s becoming more and more common to see these large melt events,” Lauren Andrews, a glaciologist with NASA’s Global Modeling and Assimilation Office, told my colleagues. “That’s because we generally have a warmer climate.”
On the other end of the planet, a new study projected that, thanks to melting ice in Antarctica, 98 percent of the world’s emperor penguin colonies may vanish by the end of the century. “There is a sea ice ‘Goldilocks’ zone,” said Stephanie Jenouvrier, a seabird ecologist at Woods Hole Oceanographic Institution and a lead author of the study, in a statement. “If there is too little sea ice, chicks can drown when sea ice breaks up early; if there is too much sea ice, foraging trips become too long and more arduous, and the chicks may starve.”
Away from imperiled fauna, there are deeper transformations also taking place. A study by three geologists found that a 2020 heat wave led to a surge in methane emissions from thawing rock formations in the Arctic permafrost, adding a new wrinkle to scientists’ fears over the ancient carbon stores being released as Earth warms.
“Normally the frozen permafrost acts as a cap, sealing methane below. It also can lock up gas hydrates, which are crystalline solids of frozen water that contain huge amounts of methane,” explained my colleague Steven Mufson. “The study said that gas hydrates in the Earth’s permafrost are estimated to contain 20 gigatons of carbon.”
And then there’s the motion of the ocean. Another study found that human-caused warming has led to an “almost complete loss of stability” in the system that drives Atlantic Ocean currents. If this key circulation — which moves warm, salty water from the tropics toward Northern Europe and then shuttles colder water south — “shuts down, it could bring extreme cold to Europe and parts of North America, raise sea levels along the U.S. East Coast and disrupt seasonal monsoons that provide water to much of the world,” reported my colleague Sarah Kaplan.