Rising sea levels, a result of water molecules expanding in warmer temperatures, increased precipitation, and the melting of mountain glaciers. Because all bodies of water have varying shapes and ocean water tends to “swell” differently depending on its starting temperature, the change in sea level is not uniform over the surface of the Earth. In the 20th century alone, sea levels rose 0.17 meters predictions for the next century range anywhere from 0.18 to 0.59 meters. While smaller projections would likely have only relatively modest impacts, the higher projections could have dramatic effects on low-lying coastal communities.
Currently, the Arctic summer sea ice is about half as thick as it was in 1950. Just like an ice cube melting in a glass of water, the melting Arctic sea ice does not contribute to sea-level rise, except for the expansion of seawater with increasing heat. However, melting Arctic sea ice may lead to global changes in ocean circulation. Water from melted ice forms a layer at the sea surface that is less dense than the underlying water since it is less salty, potentially preventing the pattern of deep ocean currents from rising to the surface. Additionally, melting sea ice speeds up the warming of the Arctic since water absorbs 80% of sunlight, about the same amount that the cover of sea ice used to reflect.
While the idea of swimming in a warmer ocean is pleasant to most human beings, increasing ocean temperatures could cause serious ecological damage. Approximately one quarter of the world’s coral reefs have died over the last few decades, a process directly tied to warming waters which weakens the coral animals.
An increase in global temperature will likely enhance the ability for severe weather, which could mean stronger and more frequent storms. Warmer temperatures cause more evaporation of water, which, as part of the water cycle eventually leads to increased precipitation and further increasing the potential for flooding.
Warmer winters mean that many deaths related to cold temperatures might be avoided and that the growing season will last longer, a possible upside to global warming. More people around the world die because of winter cold than because of summer heat. A decrease in winter deaths could offset a potential increase in summer heat-related deaths, or even lead to more lives saved as a result of the changed temperatures. With respect to longer growing seasons, there is already evidence in Europe that their growing season has been extended since the 1960s, with spring plants now blooming about 6 days earlier and fall colors coming 5 days later.
With drought affecting some regions and heat intensifying in the tropics, many areas will become unsuitable for agriculture. In tropical areas that are already dry and hot, the ability to harvest food will likely decrease even with small increases in warming. However, warmer temperatures and increased precipitation can also make previously marginal land more suitable for farming. Therefore, it is likely that, with a changing climate, a global change in the agricultural pattern will occur. Yet, it is unknown as to whether or not the increase in the usefulness of marginal lands will counterbalance an increase in drought and desertification.
In addition to potential environmental changes, the human health implications of increased global warming are very concerning. Extreme heat waves in 2003 and 2006 led to thousands of deaths in Europe, North America, and India and are likely to increase. We are also witnessing a renewed spread of diseases, likely to increase if temperatures continue to rise, including a spread of illnesses that were previously limited only to tropical areas.
Other species are also affected by global warming, most often by changes in migration patterns, shorter hibernation times, relocation to new areas, and extinction due to lack of adaptation. For example, many animals accustomed to living in the arctic regions, such as polar bears and penguins, have been forced further out of their native habitat in search of more accommodating habitat closer to the poles. Animals that migrate, such as birds and butterflies, have begun extending their migratory range closer to the poles, arriving sooner and departing later. (8)
In Summary:
Consequences of Global Warming On Health
Deadly Heat Wave: More frequent and severe heat waves will result in a greater number of heat-related deaths.
Bad Air, Allergy and Asthma: Global warming could increase smog pollution in some areas and intensify pollen allergies and asthma. Hotter conditions could also aggravate local air quality problems, already afflicting more than 500 million persons.
Infectious Disease and Food and Waterborne Illness Outbreaks: Warming temperatures, alternating periods of drought and deluges, and ecosystem disruption have contributed to more widespread outbreaks of infections like malaria, dengue fever, tick-borne encephalitis, and diarrheal illnesses. People living in poverty will be hardest hit by the global surge in infectious diseases
Dangerous Weather Events: A warmer atmosphere can hold — and dump — more moisture, contributing to more intense extreme weather events, which in turn put people’s lives at risk
Consequences of Global Warming On Weather Patterns
More Powerful and Dangerous Hurricanes: Warmer water in the oceans pumps more energy into tropical storms, making them stronger and potentially more destructive. Even with storms of the same intensity, future hurricanes will cause more damage as higher sea levels exacerbate storm surges, flooding, and erosion.
Drought and Wildfire: Warmer temperatures could increase the probability of drought. Greater evaporation, particularly during summer and fall, could exacerbate drought conditions and increase the risk of wildfires.
Intense Rainstorms: Warmer temperatures increase the energy of the climatic system and can lead to heavier rainfall in some areas. Scientists project that climate change will increase the frequency of heavy rainstorms, putting many communities at risk for devastation from floods.
Consequences of Global Warming On Wildlife
Ecosystem Shifts and Species Die-Off: Increasing global temperatures are expected to disrupt ecosystems, pushing to extinction those species that cannot adapt. The first comprehensive assessment of the extinction risk from global warming found that more than 1 million species could be obliterated by 2050 if the current trajectory continues.
Consequences of Global Warming On Glaciers and Sea Levels
Melting Glaciers, Early Ice Thaw: Rising global temperatures will speed the melting of glaciers and ice caps and cause early ice thaw on rivers and lakes. (9)
