explains that although most of Antarctica has yet to see dramatic warming, “the Antarctic Peninsula, which juts out into warmer waters north of Antarctica, has warmed 2.5 degrees Celsius (4.5 degrees Fahrenheit) since 1950.”15 However, parts of Antarctica are so cold that even if they heat by the same amount as the peninsula, it won’t be enough to melt ice.
In any case, climate change is affecting Antarctica, and that has profound implications. The U.S. National Oceanic and Atmospheric Administration reported that atmospheric carbon dioxide reached four hundred parts per million in Antarctica on May 23, 2016—the first time it’s passed that threshold in the remote area in 4 million years!
“The far southern hemisphere was the last place on earth where CO2 had not yet reached this mark,” said Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network. “Global CO2 levels will not return to values below 400 ppm in our lifetimes, and almost certainly for much longer.”16
Global warming’s impacts on Antarctica are already negatively affecting some penguin populations and could have an impact on sea levels, as ice shelves collapse. Scientists are working to learn more about what is occurring in Antarctica and what the consequences might be, but the main lesson so far is that climate change knows no boundaries and impacts in Antarctica will be felt around the world.
Oceans Take the Brunt of Global Warming
IT’S OFTEN SAID that we know as much about Mars and the moon as we do about oceans. Considering that oceans cover more than 70 percent of the earth, this should be cause for concern. At the very least, we should be doing more to protect oceans from the negative effects of human activities, including climate change, even if we don’t fully understand all that is happening under the seas.
We do know, however, that greenhouse gas emissions have a tremendous impact on oceans. As thermal sciences professor John Abraham wrote, “As humans add more heat-trapping gases to the atmosphere, it causes the Earth to gain energy. Almost all of that energy ends up in the oceans. So, if you want to know how fast the Earth is warming, you have to measure how fast the oceans are heating up.”17
Oceans and the life they support face numerous threats: pollution, overfishing, massive swirling islands of plastic waste, dead zones caused by nitrogen runoff from agricultural activities and sewage, acidification from excess CO2, oxygen depletion, and more. No oceans have escaped the consequences of human activity. French scientists who completed a two-and-a-half-year journey covering more than seven thousand miles through the Atlantic, Pacific, Antarctic, and Indian Oceans in 2012 found plastic debris in a remote ocean area that was thought to be pristine.
Researchers on the boat Tara, who were studying the effects of climate change on marine ecosystems and biodiversity, found plastic fragments in the Southern Ocean and Antarctica at levels comparable to the global average. “The fact that we found these plastics is a sign that the reach of human beings is truly planetary in scale,” said Chris Bowler, scientific coordinator of Tara Oceans, in the Guardian in 2012.18 It also reminds us that we live on a planet where everything is connected.
A 2011 study by the International Programme on the State of the Ocean (IPSO) found the combined effects of overfishing, fertilizer runoff, pollution, and ocean acidification from carbon dioxide emissions are putting much marine life at immediate risk of extinction.19 The twenty-seven scientists from eighteen organizations in six countries who participated in the review of scientific research from around the world concluded that the looming extinctions are “unprecedented in human history” and have called for “urgent and unequivocal action to halt further declines in ocean health.” The main factors are what they term the “deadly trio”: climate change, ocean acidification, and lack of oxygen. Overfishing and pollution add to the problems.
Another study by the organization, in 2013, led IPSO scientific director Alex Rogers of Somerville College, Oxford, to conclude, “The health of the ocean is spiraling downwards far more rapidly than we had thought. We are seeing greater change, happening faster, and the effects are more imminent than previously anticipated. The situation should be of the gravest concern to everyone since everyone will be affected by changes in the ability of the ocean to support life on Earth.”20
Ocean currents, upwellings, oxygen levels, acidity, and temperature are changing in ways we haven’t seen before. Assumptions we once held about the seas are no longer valid. Oceans produce more than half the oxygen we breathe and absorb up to a third of carbon dioxide emissions, as well as providing an estimated annual economic value of at least $24 trillion.
Research compiled by the IPCC has described how ingredients in the ocean’s broth are changing dramatically.21 Life in the seas is closely linked to factors in the immediate surroundings, such as temperature; acidity, or pH; salinity; oxygen; and nutrient availability. These combine at microscopic levels to create conditions that favor one form of life over another and emerge into complex ecosystems.
Oceans now absorb one-quarter to one-third of the atmosphere’s CO2. That’s good for the atmosphere but bad for organisms with calcium carbonate shells. While oceans help slow the pace of global warming, they too are absorbing too much carbon dioxide, resulting in disruption of the ocean’s pH balance. This increasing acidity causes calcium carbonate to dissolve, affecting life forms including corals, shellfish, and several species of plankton that rely on calcium for their very structure. Organisms that form the base of the oceanic food change, such as krill and shell-bearing zooplankton called pteropods, are at great risk, which puts all creatures higher up on the food chain, including humans, at risk. These organisms also store enormous amounts of carbon that will be released into the atmosphere as they die off. Even worse, phytoplankton produce much of the oxygen we breathe, and climate change is endangering these organisms. A 2015 study led by University of Leicester applied mathematics professor Sergei Petrovskii found that “an increase in the water temperature of the world’s oceans of around six degrees Celsius—which some scientists predict could occur as soon as 2100—could stop oxygen production by phytoplankton by disrupting the process of photosynthesis.”22
We’re witnessing the effects of ocean acidification on shellfish along the West Coast of North America. In 2014, a Vancouver Island scallop farm closed after losing 10 million scallops, probably because of climate change and increasing acidity.23 The U.S. National Oceanic and Atmospheric Administration has also linked oyster die-offs along the Pacific coast to climate change.24
As the IPSO points out, oceans play a key role in regulating the earth’s climate and are subject to rising levels as global warming increases. Oceans absorb much of the heat caused by excess greenhouse gas emissions. In fact, better methods to measure sea surface temperatures led scientists at the NOAA to conclude in 2015 that oceans were warmer from 1998 to 2014 than previously thought and that a much-touted slowing or hiatus in warming didn’t actually occur.25 The 2013 IPSO study found that many negative changes to the oceans are occurring much faster than anticipated and continue to accelerate, either meeting or exceeding worst-case scenarios predicted by the IPCC and others. Arctic, Greenland, and Antarctic ice sheets are declining faster than expected, causing sea levels to rise more rapidly. This, in turn, is leading to “changes in the distribution and abundance of marine species; changes in primary production; changes in the distribution of harmful algal blooms; increases in health hazards in the oceans; loss of large, long-lived fish species causing the simplification and destabilisation of food webs in marine ecosystems,” as well as increases in climate feedback loops.26 The report concludes, “The longer the delay in reducing emissions the higher the annual reduction rate will have to be and the greater the financial cost. Delays will mean increased environmental damage with greater socioeconomic impacts and costs of mitigation and adaptation measures.”
The many other human-caused
