Possible Impacts from a Changing Climate
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Projected sea level rise due to climate change could threaten coastal wetlands. Credit: Bill Wilen/USFWS |
The Intergovernmental Panel on Climate Change (IPCC) has concluded that “… Warming of the climate system is unequivocal.”
But what changes will this warming bring?
The IPCC, in its “Summary Report for Policy Makers,” describes potential future impacts that it has "very high confidence," defined as a 9 out of 10 chance, will occur.
- “Coasts are projected to be exposed to increasing risks, including coastal erosion, due to climate change and sea-level rise and the effect will be exacerbated by increasing human-induced pressures on coastal areas.”
- Sea-level rise will damage coastal wetlands through saltwater intrusion and increased erosion.
- “Many millions more people are projected to be flooded every year due to sea-level rise by the 2080s.”
- Warming in North America’s western mountains is projected to cause “decreased snowpack, more winter flooding, and reduced summer flows, exacerbating competition for over-allocated water resources.”
- “Disturbances from pests, diseases, and fire are projected to have increasing impacts on forests, with an extended period of high fire risk and large increases in area burned.”
- Heat waves will increase during the course of the century in North America, and the “growing number of the elderly population is most at risk.”
The IPCC also describes impacts that it has "high confidence," (8 out of 10 chance) will occur.
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Changes in rain and snow patterns could lead to more forest fires. Credit: Arthur Allen/USFWS |
- We will experience more frequent heavy rain and snow events.
- Drought will affect larger areas than currently.
- “The resilience of many ecosystems is likely to be exceeded this century by an unprecedented combination of climate change, associated disturbances (e.g. flooding, drought, wildfire, insects, ocean acidification) and other global change drivers.”
- “For increases in global average temperature exceeding 1.5-2.5 °C … there are projected to be major changes in ecosystem structure and function, species’ ecological interactions, and species’ geographic ranges, with predominantly negative consequences for biodiversity, and ecosystem goods and services e.g., water and food supply.”
- “Regional changes in the distribution and production of particular fish species are expected due to continued warming, with adverse effects projected for aquaculture and fisheries.”
- Projected climate change is likely to affect the health status of millions of people through: increases in malnutrition; increased deaths, disease and injury due to heat waves, floods, storms fires and droughts; and altered distribution of some infectious disease vectors. The negative health impacts outweigh any positive impacts.
- The IPCC report describes projected impacts on each continent (see report). From a continental perspective, Africa's prospects seem particularly dire.
- In polar regions, it is projected that there will be reductions in thickness and extent of glaciers and ice sheets, “and changes in natural ecosystems with detrimental effects on many organisms including migratory birds, mammals and higher predators.”
There will be detrimental impacts on infrastructure and traditional indigenous ways of life, and there is “medium confidence” that there will be reduced heating costs and more navigable northern sea routes.
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