Humans live on land, but it’s the watery parts of the planet that dictate our fate. The frozen ice at the poles and in high mountains and the vast swath of ocean that covers nearly three-quarters of the planet mean this place is primarily earth in name only. The ice—dubbed the cryosphere by scientists—and the oceans provide sustenance and livelihoods for nearly 20 percent of the world’s people, and yet climate change is putting them all in danger, according to a new groundbreaking report.
On Wednesday, the Intergovernmental Panel on Climate Change (IPCC) released it’s latest shocking report on oceans and the cryosphere. Among the findings are that human-driven climate change is already leaving a mark everywhere from the glaciers on the tallest peaks to the bottom of the sea. Those changes will continue and could accelerate in the years ahead. How rapidly the shifts occur depends largely on when humanity starts to curtail its carbon pollution problem.
“This report is unique because for the first time ever, the IPCC has produced an in-depth report examining the furthest corners of the Earth from the highest mountains and remote polar regions to the deepest oceans,” Ko Barrett, the deputy assistant administrator at the National Oceanic and Atmospheric Administration and report vice chair, said in a press briefing. “We have found that even, and especially in these places, human-caused climate change is evident.”
Indeed, recent IPCC reports have chronicled climate change on land and what the world has to do to avert global warming in excess of 1.5 degrees Celsius (2.7 degrees Fahrenheit). Another group also recently put out a report on the extinction crisis. Together, that trio of reports paints a picture of humanity pushing the planet to the brink and highlights the solutions at our disposal to walk back from the edge. This report only adds more evidence for the urgent need for action.
Among the starkest findings is that the oceans are being bifurcated in two, a warming top and cut-off depths. The ocean has absorbed double the amount of heat over the past 25 years compared the previous 25 years. That added warmth has caused the top 200 meters (656 feet) of the seas to warm faster than the depths, a process that Nathan Bindoff, a report author and oceanographer from the University of Tasmania, called “preferential warming.”
That’s disrupting a process known as upwelling that’s crucial for providing nutrients to the surface and oxygenating the water column. Imagine the ocean is like a Ferris wheel with cold water rising up, pushing warm water away until it eventually cools and sinks. But in the changing ocean, the lighter, warm water has basically knocked the Ferris wheel out of service for parts of the ocean, essentially acting as a cap, keeping cooler, dense water locked in place below.
The report notes that this stratification coupled with oxygen deprivation and ocean acidification is already in part causing California and Humboldt currents—two of the most productive ecosystems in the world—to struggle. No matter the future scenario, this stratification and other impacts of climate change, such as rising temperatures and dips in plankton and other sea creatures that form the base of the food chain, “the ocean is projected to transition to unprecedented conditions” over the rest of the 21st century, the report found.
The dangerous changes to the ocean don’t even begin to address the impacts of rising seas. Under all climate change scenarios, coastal areas will see what the report euphemistically calls “extreme sea level events”—that would be floods to you and me—that were once once-in-a-century will become annual occurrences by century’s end. But devastating effects will impact unnumbered people far sooner.
“Many low-lying megacities and small islands (including SIDS) are projected to experience historical centennial events at least annually by 2050,” the report authors wrote.
This is in part why low-lying island nations could become uninhabitable by the 2050s as the quickening drumbeat of sea level rise pollutes their fragile freshwater aquifers and storm surge swallows people’s homes. Even wave heights are projected to change, with the biggest waves climbing higher due to sea level rise and shifting wind patterns.
If the hotter, more acidic oceans sound terrifying, then the changes to ice are just as daunting. The report chronicles the rate of ice loss at both poles and in the high peaks around the world. When comparing the period of 2007-2016 to 1997-2006, the report shows Greenland’s ice loss has doubled while Antarctica’s has tripled, with all that extra melted ice pouring into the ocean and raising sea levels. The report also shows ice and snowpack are disappearing on more inhabited landmasses, reducing water availability for people living down valley. In a particularly stark finding, the report indicates that up to 90 percent of low elevation mountain snowpack could disappear if carbon emissions continue to rise unabated. Under a more hopeful scenario where humans start drawing down emissions by 2030, “only” 10 to 40 percent of low elevation mountain snowpack will disappear.
And that’s where the report follows in its forebearers’ footsteps most closely. While it paints a dire picture of the future, it also highlights that we have choices. And the fate of a huge swath of humanity hangs in the balance. Coastal populations are expected to boom in the coming decades, and the report estimates that 1 billion people could call low-lying coastal areas home by 2050. Another 740 million to 840 million people are projected to live in mountainous areas along with 4 million people living in the Arctic. All told, that’s 20 percent of the world’s future population of 9 billion people.
The report touts the benefits of offshore wind and wave energy as a way oceans can play a role in helping mitigate climate change. The high seas themselves can also sequester carbon, though Barrett warned that oceans will eventually take up less and less carbon dioxide as they warm. Plus all that extra carbon pollution contributes to ocean acidification, so it’s probably best to not rely on them to save our asses.
Adaptation planning is also crucial since even in the best scenario, glaciers will still melt, seas will still rise, and, well, you get my drift. The report argues we need more cooperation, including with indigenous groups who can tap traditional knowledge, and to foster ecosystems that can protect us. In some cases, people may need to relocate to higher ground or to locations where water resources are more plentiful, which will again require everyone to cooperate.
The world has shown little appetite to take a collaborative approach to these types of adaptation projects let alone drawing down emissions to-date, but the tide will have to turn if humanity is to have any chance of staying above water.