The ocean is not doing well.
The seas, which contain approximately 332,519,000 cubic miles of water, heat, rise, acidify and lose oxygen. And a new comprehensive UN climate special report, released Wednesday, presents an encyclopedic review of how the Earth’s oceans and ice caps have been altered as the world continues to warm.
More than 100 scientists from 36 countries (who cited more than 6,900 studies) wrote the austere dispatch, titled “Special Report on the Ocean and Cryosphere in a Changing Climate”.
However, today’s troubled seas are just the beginning of the ocean’s transition. This is because the oceans are the true custodians of climate change: most of the heat trapped by humanity on the planet is absorbed by the ocean. And modern civilization won’t stop saturating the atmosphere with heat-trapping carbon dioxide anytime soon.
âMore than 90 percent of the heat from global warming warms the oceans,â said Josh Willis, a NASA oceanographer who played no role in the UN report.
âGlobal warming is really warming the oceans,â said Willis.
For everyone inhabiting the planet in the decades and centuries to come, this will mean, among other effects, rising sea levels and warming. The problem will get worse, but humanity can still limit the consequences, including by drastically reducing carbon emissions.
“If we sharply reduce emissions, the consequences for people and their livelihoods will still be difficult, but potentially more manageable for the most vulnerable,” said Hoesung Lee, chairman of the Intergovernmental Panel on Climate Change. (IPCC) of the UN, in a press release. .
“Global warming is really a warming of the oceans.”
“Even with aggressiveness [carbon] mitigation efforts, we will always have to deal with the consequences of a changed ecosystem and environment, ânoted Jeremy Mathis, longtime Arctic researcher and current director of the board of directors of the National Academies of Sciences. Mathis had no involvement with the UN IPCC report.
(Reminder: Earth’s carbon dioxide emissions to air are skyrocketing. CO2 levels haven’t been this high for at least 800,000 years – though more likely millions of years. of carbon are now increasing at rates unprecedented in both and all-time highs.)
The report is comprehensive. But here are some of its many takeaways:
1. Sea level rise will probably be worse than you imagine
The UN report concluded that sea level rise will continue for centuries. In a fairytale world, where society can curb the Earth’s warming to 1.5 degrees Celsius (or 2.7 degrees Fahrenheit) above pre-industrial revolution temperatures (this scenario is now nearly impossible to be achieved), sea level will likely rise one to two feet by the end of the century, according to the report.
But if emissions continue to rise to consistently high levels, the IPCC has found that sea level will rise from nearly two feet to over three and a half feet (i.e. over a meter !). This is because the most massive ice caps on Earth, over Antarctica and Greenland, “are expected to lose mass at an increasing rate throughout the 21st century and beyond,” according to the report.
Even so, UN climate estimates are often conservative. Accelerated melting of the Greenland and Antarctic ice caps – who are currently both experiencing accelerated melting – could cause sea level to rise much more than the report considers.
Sea level rise documented by satellite observations.
âI don’t think there’s a science that rules out two meters by 2100,â NASA’s Willis said. “I think most people who study Greenland and Antarctica think [sea level rise] could be higher than current projections.
In large part, this is because warming oceans are eating away and melting the edges of glaciers, Willis said, noting that this is a big effect that Arctic and ocean researchers are starting all over. just to grab.
And guess what? The oceans are sure to continue to warm. âDuring the 21st century, the ocean is expected to change to unprecedented conditions with increased temperatures,â among other changes, the report concluded.
2. The ocean feeds storms
The IPCC report points out that tropical cyclones, which include hurricanes, are expected to become increasingly violent, especially with stronger winds and extreme rainfall. This is because cyclones feed on warm ocean waters. Storms increase their circumference by sucking up evaporated seawater and create stronger winds by converting water vapor into energy.
Hurricane Dorian photos illustrate devastation and destruction in Bahamas
Research has shown that the remarkably warm waters prevailed over other factors, allowing recent Atlantic storms to escalate into powerful cyclones.
But a cyclone doesn’t need strong winds to be devastating. Storms these days often carry more water, and warmer sea surface temperatures are the reason.
The ever-increasing heat content of the oceans.
âThe oceans are much warmer than they were 50 years ago,â said Mathis, former director of the National Oceanic and Atmospheric Administration (NOAA) Arctic Research Program. He noted that warmer oceans evaporate more water vapor into the atmosphere, providing storms with more fuel.
âWarmer oceans will lead to extreme precipitation,â Mathis said, citing how Tropical Storm Imelda recently flooded the Texas coast. Imelda became one of the wettest cyclones in US history. “This storm has started [in intensity] in 12 hours, “Mathis noted.” Suddenly the area received 42 inches of rain. “
3. Everything changes
The special report focuses not only on the ocean, but on the planet’s water everywhere – also known as the hydrosphere. That means glaciers atop Mount Everest, ice caps in Greenland, and ocean waters thousands of feet below the surface.
âI think the most important part of this work and this message is that anthropogenic climate change is affecting all aspects of the hydrosphere, a key ingredient of life,â said Jeremy Owens, marine biogeochemist at Florida State. University which had no involvement in the report.
Importantly, Earth’s ice caps and glaciers are “shrinking,” the report pointed out. Indeed, glaciers on all continents except Australia (which does not have one) are retreating or dying. Most importantly, the mountains lose snow, which is vital for providing water to people (via snowmelt) during the hot or dry season.
Greta Thunberg shames apathetic adults at UN Climate Action Summit
“The snow is good, but we have less,” said Heidi Steltzer, lead author of the IPCC report, on a call with reporters.
The consequences of a warming ocean, however, will be many. Climate change, Owens noted, will affect water temperature (which has dramatic consequences for marine life), the ability of nutrients to disperse in the ocean, ocean acidity (as the oceans absorb the CO2 from the air) and oxygen levels in the water – that sea creatures need to breathe.
4. The Arctic we once knew is gone
The Arctic is the most disturbed place on Earth. This is because it has warmed more than twice as much as the rest of the globe. As a result, the large sea ice cover that covers the vast Arctic Ocean is being lost.
This week alone, Arctic sea ice fell to its second lowest level on record, more than 2 million square kilometers below the average minimum extent of ice in previous, colder decades. âRapid changes in the Arctic are among the clearest indicators of anthropogenic climate change,â Zack Labe, climatologist and Ph.D. candidate at the University of California, Irvine, told Mashable.
The report found that if civilization stabilizes the climate at 1.5 degrees Celsius, the Arctic will continue to thin out, but will likely not become completely ice-free by the end of summer (September) until the end of the summer (September). once every 100 years or so.
But if the planet warms to 2 degrees Celsius this century (or 3.6 degrees Fahrenheit), the Arctic will likely be ice free in September once every three years. The planet has warmed by 1.1 degrees Celsius already since the late 1800s. So 1.5 Celsius is just around the corner.
5. Trust your eyes
The research presented in this IPCC report is valuable, said Mathis of the National Academies of Sciences. But “you don’t have to be a scientist anymore to see what’s going on,” he said.
This is because the consequences of an ever-warming ocean and atmosphere are easily visible to everyone.
Twice in the past three years, the Texas Gulf Coast has experienced storms that have dropped more than 40 inches of rain, Mathis noted, including the largest rain in U.S. history.
And with Tropical Storm Imelda, Texas has probably experienced five “500-year floods” (which are expected to have a 1 in 500 chance of occurring in any given year) in the past five years.
“It’s extraordinary, it’s exceptional,” said Mathis. “You don’t have to be a scientist to know this isn’t normal.”
âTrust your own eyes,â he added.
The warming and disturbed oceans are there. And with increasing carbon emissions, they are expected to heat up, increase and continue to rise. It is a rule of physics.
âWe’re looking at the barrel of some significant economic and environmental impacts that have already started,â NASA’s Willis said, noting projections of sea level rise.
“All projections show they are going to get worse.”