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 also shown that warming ocean waters are increasing the incidence of waterborne illnesses, including those caused by toxic bacteria in shellfish.
Climate change affects the very basics that humans need to stay healthy and alive: clean air, safe water, productive and uncontaminated soils for growing food, and adequate shelter. According to the WHO, climate impacts on these basic needs will lead to 250,000 additional deaths a year, “from malnutrition, malaria, diarrhoea and heat stress” between 2030 and 2050. Weather-related natural disasters have more than tripled since the 1960s, resulting in more than 60,000 deaths a year, mostly in developing nations.30 The young, elderly, and poor are at especially great risk.
This is costly to the economy as well as to human health and survival. The World Bank estimates that a severe influenza pandemic could cost the world economy $3 trillion. Environment Canada says air pollution alone costs the Canadian economy billions of dollars a year because of increased health care costs, missed workdays, and reduced productivity.
The 2015–16 spread of the Zika virus also gives us a glimpse of what to expect from climate change. Researchers believe the virus, which is transmitted by mosquitoes, could spread farther north as warmer, wetter weather provides ideal conditions for the mosquitoes to breed. The spread in South America is probably linked to wetter and warmer conditions there. Other mosquito-borne illnesses could also spread.
Reducing the threat of global warming and finding ways to adapt to unavoidable change will help people around the world “deal with the impact of heat, extreme weather, infectious disease and food insecurity,” according to the WHO. Climate change affects human health in multiple ways. Increased extreme weather causes flooding and droughts, which influences food production, water, and sanitation. Pathogens that plague humans, livestock, and crops spread more widely. The WHO noted that diseases such as cholera, malaria, and dengue are especially sensitive to weather and climate changes: “Climate change is already causing tens of thousands of deaths every year from shifting patterns of disease, from extreme weather events, such as heat-waves and floods, and from the degradation of water supplies, sanitation, and impacts on agriculture.” And it will get worse if we fail to address the problem.
Global warming and pollution also affect ailments such as asthma and allergies. A warming planet means longer growing seasons and stimulated plant growth in many areas (although it’s causing drought and reduced plant growth in some parts of the world). Research shows the U.S. pollen season lengthened by about sixteen days from 1995 to 2014 and the ragweed season by anywhere from a day to sixteen days, with greater increases moving north. The Public Health Agency of Canada says Canada’s ragweed season was close to a month longer in 2014 than in 1995 because of warming temperatures.
And rising atmospheric CO2 actually increases pollen production. Tests conducted by U.S. Department of Agriculture weed ecologist Lewis Ziska showed pollen production doubled from five to ten grams per plant when CO2 in the atmosphere went up from 280 parts per million in 1900 to 370 in 2000,31 according to a USA Today article. That could double to twenty grams by 2075 if greenhouse gas emissions continue to rise.
Add to that the extreme weather impacts of climate change that can exacerbate allergy symptoms and other respiratory problems (rain and higher temperatures create more molds and fungi in some places; more dust contributes to allergies and asthma in drought-stricken areas), plus the all-around increases in ground-level ozone, smoke, and pollution, and you’ve got a recipe for mass discomfort, illness, death, and rising health care costs.
We still don’t fully understand the multiple impacts of global warming on allergies or what else may be contributing to the problem. Increased chemical exposure and the hygiene factor—which shows lack of exposure to germs and the outdoors early in life can make people more prone to allergies—may also be involved.
The effects on allergies don’t mean people should stay indoors. Getting outside offers numerous physical and mental health benefits. Research even shows that kids who
