Impacts
How is additional warming changing the planet?
Our forecast
Since climate change is difficult to observe with the naked eye, it’s hard to tell how its having an impact. Since 1990 the world has warmed about 1 degree. Driven by expected additional releases of heat-trapping gases, leading scientists expect the Earth to warm more. Based on current trends, MIT forecasts another 2 to 5ºF in 30 years, and 5 to 7ºF by the end of this century. With these increases, scientists warn that our recent bouts with “weird weather” may become much more common in the future.
Evidence
Pollution we put up into the air today can continue warming the Earth for over a hundred years, so the decisions made today will have repercussions for centuries. As carbon pollution continues to grow, NASA satellites show the Earth is steadily warming. With temperatures warming just over a degree, the world today is different than it was just a generation ago. Scientists can document declining polar ice, higher sea levels, more intense wildfires, and much more.
How are climate & weather different?
Climate means the long term behavior of weather. Weather is local and short-term; climate describes the average weather for a region at a given time of year based on historical patterns. Climate change means the average temperature and precipitation is not following those old patterns.
Where is there scientific agreement?
The world’s leading scientific organizations, including MIT and NASA, agree that human-caused climate change is happening and just a few more degrees of warming will increase the risk of intense storms, sea level rise and other extreme weather events.
How much warming has happened?
People have caused about 1.5ºF of unnatural warming by putting greenhouse gases into the air since 1889. While it may not sound like much, the extra warming has been linked to some natural disasters such as wildfires in the U.S. and drought in the Mediterranean.
More than scientists
The military, including the CIA and Department of Defense, are preparing for a warmer world. Leading businesses, including the world’s largest oil companies, are funding climate research — their questions are not whether it is real but how to prepare and cope with the coming changes.
Climate impacts are projected to introduce large economic costs that could be even greater without appropriate preventative measures. Leading businesses, such as Microsoft and General Electric, are taking action to reduce their own emissions and support broader policies to lower emissions around the world. Many, such as Shell and Southern Company, are indexing executive pay to emission reductions.
Medical professionals, including the Centers for Disease Control and the American Lung Association, warn that climate change is already having an impact on public health. More extreme temperatures and severe weather events can affect human health by worsening air pollution, asthma and allergies; creating conditions for disease-carrying pests to spread (West Nile, lyme disease); and increasing extreme heat and cold-related illnesses.
Changes in our climate have put large amounts of stress on both plants and animals. Some species are becoming endangered because of altered habitats (such as melting of the permafrost) or shifting habitat ranges and others have become extinct altogether. Extreme events like flooding, drought, and wildfires can drastically affect species populations and more gradual events like warming temperatures, ocean acidification and sea level rise put even more stress on these ecosystems. Climate change presents a major threat to earth’s natural processes and scientists are monitoring for “tipping points”, self perpetuating cycles that could irreversibly worsen projected impacts. Such tipping points include the collapse of the Greenland or West Antarctic Ice Sheet or massive die-off of the Amazon Rainforest.
Sources and Citations
- NASA, “Climate Change: Impacts”: www.climate.nasa.gov.
- MIT, “Climate Change: Impacts”: www.climate.nasa.gov.
- MIT, “Climate Change: Impacts”: www.climate.nasa.gov.
Photographs
- Fred Hotchkins, NASA.