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 Assumptions we once held about the seas are no longer valid.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 stressors on the oceans—including overfishing, pollution, agricultural runoff, and sewage—compromise the resilience of oceans in the face of climate change.
Oceans, land, and atmosphere are intricately connected to climate systems and changes. Wind and currents move warmer water toward the poles and cooler water toward the equator. Heat energy is transferred between the sun, atmosphere, land, and oceans through radiation, convection, and conduction. As levels of greenhouse gases such as CO2, water vapor, methane, and ozone increase, warming occurs, with the oceans absorbing much of the warming. This affects ocean currents, and because warmer water expands and global warming causes glaciers and sea ice to melt, sea levels rise. Warmer oceans also alter climate patterns, increasing the frequency and severity of events like tropical storms. As the U.S. EPA points out, “Interactions between the oceans and atmosphere occur slowly over many months to years, and so does the movement of water within the oceans, including the mixing of deep and shallow waters. Thus, trends can persist for decades, centuries, or longer. For this reason, even if greenhouse gas emissions were stabilized tomorrow, it would take many more years—decades to centuries—for the oceans to adjust to changes in the atmosphere and the climate that have already occurred.”27 According to the EPA, global average sea levels have increased by about six-tenths of an inch per decade since 1880, but the rate has increased in recent years to an inch per decade. Sea level increases vary by region, and the EPA reports that increases have been as high as eight inches between 1960 and 2014 along parts of the U.S. mid-Atlantic and Gulf coasts.
Even relatively small increases in sea level can cause shoreline erosion and changing coastal habitats, wetland destruction, contamination of agricultural areas and aquifers, and damage to human infrastructure. If climate change isn’t curtailed, many highly populated areas will eventually be underwater. Because the oceans have already absorbed so much heat, scientists predict that sea level increases will displace 20 percent of the world’s human population over the coming decades, even if global average temperature increases are kept below two degrees Celsius, from areas including Rio de Janeiro, New York City, Vancouver, London, Shanghai, and many others. Many low-lying islands will be completely submerged. Some studies predict sea levels could rise between 2.5 and 6.5 feet by 2100, or as much as 23 feet if the Greenland ice sheet were to melt.28
Increasing storm surges, rapid spread of invasive species and ocean-related diseases, and collapsing polar ice shelves are also consequences of warming oceans. And scientists believe that warming oceans could change global ocean currents that help regulate the world’s temperature.
Although our knowledge of oceans and their role in global climate systems is continually improving, we still have a lot to learn. But we know enough to see that we have to start treating them differently if we are to survive and remain healthy. After all, we can’t move to Mars or the moon.
Climate Crisis Spells Trouble for Human Health
WHAT IF WE could reduce worldwide deaths from disease, starvation, and disaster while improving the health of people everywhere? According to the World Health Organization (WHO), we can.29 “Previously unrecognized health benefits could be realized from fast action to reduce climate change and its consequences,” said a news release about the WHO’s first global conference on health and climate in Geneva in summer 2014, adding, “changes in energy and transport policies could save millions of lives annually from diseases caused by high levels of air pollution.” Encouraging people to use public transit, bicycle, and walk instead of driving would cut traffic injuries and vehicle emissions and promote better health through increased physical activity.
Studies show that heart attacks and respiratory illness because of heat waves, altered transmission of infectious diseases, and malnutrition from crop failures can all be linked to a warming planet. And economic and political upheaval brought on by climate change can damage public health infrastructure, making it difficult for people to cope with the inevitable rise in sickness. Research has