Global climate change affects the planet in many ways, causing rising temperatures, melting ice & sea level rise, and more extreme weather events, resulting in longer, more intense heat waves, floods, and droughts. All of these threaten ecosystems, food supplies, and human health.
Carbon dioxide in the atmosphere is 50% higher than it was before the start of the Industrial Revolution, due to increasing greenhouse gas emissions. Climate change may be our planet’s greatest existential threat.
Increasing Temperatures and Sea Levels
According to the National Oceanic and Atmospheric Administration (NOAA) and the Intergovernmental Panel on Climate Change (IPCC), average global temperatures have increased by 2°F from 1850 to 2023. This increase is expected to be 3°F within the next few decades and may be as much as 7°F by 2100. The summer of 2023 was Earth’s hottest on record, 0.4°F warmer than any other summer, and 2.1°F warmer than the average summer between 1951 and 1980.
Average sea level has risen 8–9 inches since 1880 and is expected to rise at least another foot by the year 2100 (maybe by as much as 6 feet). The Arctic is especially vulnerable to the effects of climate change. It is warming at least twice as fast as the global average. Climate reference glaciers have lost ice for the past 36 years in a row. Between 1979 and 2021, the Arctic Ocean has lost 31,100 square miles of sea ice per year and will likely become virtually ice-free in late summer if current projections hold.
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Impacts of Climate Change on the Weather
As global temperatures climb, widespread shifts in weather systems occur, making events like droughts, hurricanes, wildfires, and floods more intense & unpredictable. Climate change may cause severe drought in one region while making floods more likely in another.
Warmer air holds more moisture, making tropical cyclones wetter & stronger. The latest IPCC report predicts that the frequency of Category 4 and 5 hurricanes is expected to increase.
Impacts on Marine Ecosystems
Oceans are taking the brunt of the climate crisis. Covering more than 70% of the planet’s surface, oceans absorb 93% of all the heat that’s trapped by greenhouse gases. Temperature-sensitive fish and other marine life are already changing migration patterns, sending food webs and important commercial fisheries into disarray. And the frequency of marine heat waves has increased by more than a third, leading to mass die-offs of plankton & marine mammals.
The ocean absorbs about 30% of the carbon dioxide released into the atmosphere, which leads to its gradual acidification, altering the fundamental chemical makeup of the water and threatening marine life. Animals like corals, oysters, and mussels will feel these effects first, as acidification disrupts the calcification process required to build their shells.
Coral reef ecosystems are home to thousands of species, which rely on healthy coral reefs to survive. Sea level rise causes sediment to smother corals. Coral reefs are also vulnerable to bleaching, and stronger hurricanes can physically destroy reefs.
Impacts on Terrestrial Ecosystems
Land-based ecosystems are faring no better. Climate change is increasing outbreaks of pests, invasive species, and pathogen infections in forests. It’s changing the kinds of vegetation that can thrive in a given region and disrupting the life cycles of wildlife, changing the composition of ecosystems and making them less resilient.
Climate change alters or destroys the habitats in which wildlife has evolved over millennia. Half of all animal species in the world’s most biodiverse places are at risk of extinction. And species already suffering biodiversity crises (e.g., from converting wild places to farmland) and direct exploitation (e.g., from overfishing) are even more threatened. More than 500,000 animal species have insufficient habitat for long-term survival.
Disappearing wetlands in the Prairie Pothole Region of the US means the loss of watering holes and breeding grounds for millions of migratory birds. And sea level rise is inundating or eroding away many coastal habitats, where hundreds of species of birds, invertebrates, and other species live.
Human and Economic Impacts of Climate Change
According to the 2018 National Climate Assessment, unless action is taken, climate change will cost the US economy as much as $500 billion per year by the end of the century. Entire local industries, from commercial fishing to tourism to husbandry, are at risk of collapsing, along with the economic support they provide. Recovering from the destruction wrought by extreme weather events is also getting more expensive. In 2021, the price tag of weather disasters in the US totaled $145 billion.
Impacts on Agriculture
In a warming world, growing crops is more unpredictable, and raising livestock becomes more difficult. Shifting precipitation patterns cause unpredictable floods and longer-lasting droughts. Pests, pathogens, and invasive species become harder to predict & control. Healthy soil has good moisture & mineral content and is loaded with bugs, bacteria, fungi, & microbes. But degrading soil quality, especially in areas where industrial, chemical-dependent monoculture farming is practiced, is accelerated by climate change.
Impacts to agricultural systems pose a direct threat to the food supply. And food shortages and price hikes do not affect everyone equally. Wealthier people will continue to have more options for accessing food, while billions of others will be plummeted into food insecurity, adding to the billions that already have moderate or severe difficulty getting enough to eat.
Impacts on Wildfire
Warming temperatures have extended & intensified wildfire season, creating conditions where fires spread faster and burn longer. The number of large wildfires doubled between 1984 and 2015 in the western US, and in California, the annual area burned by wildfires increased 500% between 1972 and 2018. By 2050, the amount of land consumed by wildfires is projected to further increase by two to six times. Even in traditionally rainy regions, wildfires are projected to increase by 30%.
Impacts on Human Health
Our ways of life have all developed in the context of relatively stable climates. Global climate change shakes this foundation and promises to alter every aspect of society, which could lead to famine, disease, war, & displacement.
Heat stress is one of the deadliest weather conditions. Heat waves are the leading cause of weather-related fatalities in the US. With every 3.6°F rise in average global temperature, an additional one billion people face heat stress risk.
Climate change increases exposure to hazardous wildfire smoke and ozone smog, which are particularly harmful for those with pre-existing illnesses like asthma or heart disease. Insect-borne diseases become more prevalent as their carriers are able to exist in more regions and thrive for longer seasons. In the past 30 years, the incidence of Lyme disease in the US has nearly doubled.
Impacts on Infrastructure
Severe storms and coastal flooding damage & destroy infrastructure, costing billions of dollars to repair or replace. Infrastructure includes homes & other buildings, roads & bridges, electrical grids, drinking & wastewater systems, and other parts of our transportation & communication systems. Most existing infrastructure was not designed with climate change in mind.
Existing infrastructure may not be able to withstand extreme weather events that bring heavy rains, floods, wind, snow, or temperature changes. Increased temperatures require more indoor cooling, which puts stress on the energy grid. Sudden heavy rainfall can exceed storm water drainage capacity and lead to flooding that shuts down highways, other transportation routes, & businesses.
Coastal infrastructure is at risk from sea level rise. Nearly 40% of the US population live in coastal counties. Sea level rise can lead to coastal erosion and high-tide flooding. Some communities could end up at or below sea level by the year 2100, devastating island nations and densely-populated coastal cities.
Impacts on Water Supply
Changing patterns in the distribution of precipitation makes planning for adequate water supplies more difficult. Some areas are experiencing heavier rain events while others are having more droughts.
Sea level rise also harms water supplies, as encroaching seawater invades freshwater inland aquifers. Saltwater incursion is already reshaping life in nations like Bangladesh, where one-quarter of the land lies less than 7 feet above sea level.
Mountain snowpack is an important source of fresh water in some areas, like the western US. As the snow melts, fresh water becomes available for use. But as temperatures warm, there is less snow and it melts earlier in the summer, and snowpack is a less reliable source of water.
Decreasing Equity of Impacts
The climate crisis makes existing inequities worse. Though wealthy nations, such as the US, have emitted the lion’s share of historical greenhouse gases, it’s the developing countries, which may lack the resources to adapt, that will bear the brunt of the costs. In some cases, low-lying island nations, like many in the Pacific, may cease to exist at all. Climate change will drive displacement and economic instability. It’s already occurring.
Even in wealthier nations, disparities will grow between those who can shield themselves from the realities of climate change and those who cannot. They will have homes with cool air during heat waves and will be able to evacuate when a hurricane is headed their way. They will be able to buy increasingly expensive food and access treatment for health problems. Billions of others who cannot will pay the highest price for the climate pollution they did not produce.
Future Impacts of Climate Change
The severity of impacts caused by climate change will depend on future human activities. More greenhouse gas emissions will lead to more climate extremes and widespread damaging effects. Those future effects will depend on the total amount of carbon dioxide emitted. If we can reduce emissions, we may avoid some of the worst impacts.
The first wave of impacts can already be felt in our communities and seen on the nightly news. The World Health Organization says that, between 2030 and 2050, climate change is expected to cause an additional 250,000 deaths per year from things like malnutrition, insect-borne diseases, and heat stress. And the World Bank estimates that climate change could displace more than 140 million people within their home countries by 2050.
Climate mitigation, our ability to reverse climate change, hinges on the successful enactment of policies that yield deep cuts to carbon pollution, end our dependence on fossil fuels, and prioritize people & ecosystems. And these actions must be taken quickly to ensure a healthier present day & future. Climate adaptation is no longer optional, it’s necessary, particularly for the world’s most vulnerable populations.
