The best of EcoWatch, right in your inbox. Sign up for our email newsletter!
The Ocean Is Running Out of Oxygen, Largest Study of Its Kind Finds
The International Union for Conservation of Nature (IUCN) report combined the work of 67 scientists from 17 countries to conclude that oxygen levels in the ocean had declined around two percent since the mid-20th century, and the volume of waters entirely deprived of oxygen had increased four-fold since the 1960s. The report was released Saturday at the COP25 UN Climate Change Conference in Madrid, CBS News reported, in hopes of persuading world leaders to protect the oceans from future oxygen loss.
"Urgent global action to overcome and reverse the effects of ocean deoxygenation is needed," IUCN Global Marine and Polar Programme director Minna Epps said, as CBS News reported. "Decisions taken at the ongoing climate conference will determine whether our ocean continues to sustain a rich variety of life, or whether habitable, oxygen-rich marine areas are increasingly, progressively and irrevocably lost."
Ocean deoxygenation comes from two major causes: nutrient pollution and the climate crisis.
Nutrient pollution has long been understood as a threat to ocean oxygen levels. Run-off from sewage and agriculture, as well as nitrogen from fossil fuel emissions, encourages the excessive growth of algae, which depletes oxygen. This process is relatively fast and easy to fix.
But in recent years scientists have come to understand how rising ocean temperatures are also lowering oxygen levels. Warmer water can't hold as much oxygen, and it is also more buoyant, which means it mixes less with deeper, less-oxygenated water, reducing oxygen circulation overall. Rising temperatures are likely responsible for around 50 percent of the oxygen loss in the top 1,000 meters (approximately 3,281 feet) of the ocean, which are also the most abundant in biodiversity. Climate-change-related oxygen loss is difficult or impossible to reverse.
"This is one of the newer classes of impacts to rise into the public awareness," Kim Cobb, a Georgia Tech climate scientist who was not involved with the study, told The New York Times.
While a two percent decrease in overall oxygen levels might not sound like a lot, there are environments where a small change in oxygen can make a huge difference, report editor Dan Laffoley explained to The New York Times.
"[I]f we were to try and go up Mount Everest without oxygen, there would come a point where a 2 percent loss of oxygen in our surroundings would become very significant," he said.
He also said the oxygen loss was not evenly distributed. Some waters in the tropics had seen a 40 to 50 percent decrease in oxygen. The number of oxygen-deprived areas has also increased, from 45 before the 1960s to 700 in 2011, according to the report.
This oxygen loss is especially threatening to larger fish species like marlin, tuna and sharks, who require more energy, BBC News reported. These species are already moving closer to the surface for oxygen, which puts them at greater risk from overfishing. Cobb also pointed to the mass die-offs of fish along the coast of California as another symptom of falling oxygen levels.
Loss of oxygen could also impact Earth systems that extend beyond the ocean, such as the nitrogen and phosphorus cycles.
"If we run out of oxygen it will mean habitat loss and biodiversity loss and a slippery slope down to slime and more jellyfish," Epps said, according to CBS and BBC News. "It will also change the energy and the biochemical cycling in the oceans and we don't know what these biological and chemical shifts in the oceans can actually do."
The report warned that if nations continue to emit greenhouse gases at business-as-usual levels, the ocean will lose three to four percent of its oxygen by century's end.
"To stop the worrying expansion of oxygen-poor areas, we need to decisively curb greenhouse gas emissions as well as nutrient pollution from agriculture and other sources," Laffoley said, according to BBC News.
EcoWatch Daily Newsletter
By Hans Nicholas Jong
The Indonesian government has backed down from a decision to scrap its timber legality verification process for wood export, amid criticism from activists and the prospect of being shut out of the lucrative European market.
Viruses, pollution and warming ocean temperatures have plagued corals in recent years. The onslaught of abuse has caused mass bleaching events and threatened the long-term survival of many ocean species. While corals have little chance of surviving through a mass bleaching, a new study found that when corals turn a vibrant neon color, it's in a last-ditch effort to survive, as CBS News reported.
- Coral Reef Tipping Point: 'Near-Annual' Bleaching May Occur ... ›
- Coral in Crisis: Can Replanting Efforts Halt Reefs' Death Spiral ... ›
- 2020 Great Barrier Reef Bleaching Event Is Most Widespread to Date ›
During summer in central New York, residents often enjoy a refreshing dip in the region's peaceful lakes.
But sometimes swimming is off-limits because of algae blooms that can make people sick.
- Algal Blooms Can be Deadly to Your Dogs - EcoWatch ›
- Every Mississippi Beach Is Closed Due to Toxic Algae - EcoWatch ›
- Toxic Algal Blooms Connected to Climate Change and Industrial ... ›
More than 40 million doctors and nurses are in, and they are prescribing a green recovery from the economic devastation caused by the new coronavirus.
- A 'Green Stimulus' Could Battle Three Crises: Coronavirus ... ›
- German Business Leaders Call for Climate Action With COVID-19 ... ›
- Canadian Groups Fight for a Just Covid-19 Recovery - EcoWatch ›
The U.K. government has proposed delaying the annual international climate negotiations for a full year after its original date to November 2021 because of the coronavirus pandemic.
By Jared Kaufman
Upcycled food is now an officially defined term, which advocates say will encourage broader consumer and industry support for products that help reduce food waste. Upcycling—transforming ingredients that would have been wasted into edible food products—has been gaining ground in alternative food movements for several years but had never been officially defined.
- Chefs Are Going Back to Their Roots for Local, Sustainable Foraged ... ›
- This Montreal Company Turns Juice Pulp Into Food - EcoWatch ›
How to Lower Your Coronavirus Risk While Eating Out: Restaurant Advice From an Infectious Disease Expert
By Thomas A. Russo
As restaurants and bars reopen to the public, it's important to realize that eating out will increase your risk of exposure to the new coronavirus.
- Why Wear Face Masks in Public? Here's What the Research Shows ... ›
- How to Stay Healthy at Home During the Coronavirus Lockdown ... ›
- How Do You Stay Safe Now That States Are Reopening? - EcoWatch ›