Impact of Climate Change

"The research community provides much information to support discussions on 'dangerous climate change'. Recent observations show that societies and ecosystems are highly vulnerable to even modest levels of climate change, with poor nations and communities, ecosystem services and biodiversity particularly at risk. Temperature rises above 2^oC will be difficult for contemporary societies to cope with, and are likely to cause major societal and environmental disruptions through the rest of the century and beyond." -- Synthesis Report from the Climate Change Congress (2009)

"Climate change is occurring, is caused largely by human activities, and poses significant risks for—and in many cases is already affecting—a broad range of human and natural systems. Individually and collectively, these changes pose risks for a wide range of human and environmental systems, including freshwater resources, the coastal environment, ecosystems, agriculture, fisheries, human health, and national security, among others." -- U.S. National Research Council (2010)

Unfortunately, the equilibrium global surface air temperature change due to a doubling of CO₂ from 280 ppm (pre-Industrial Revolution) to 560 ppm is likely to be in the range 2 to 4.5^oC with a best estimate of about 3^oC, and is very unlikely to be less than 1.5^oC (Knutti and Hegerl, 2008; IPCC, 2007). As this section of Web pages will reveal, 3 ^oC will have serious negative consequences for life on this planet.

Topics below are forthcoming:

Agriculture, Fisheries, and Food Production
Public Health
     Allergies & Asthma
National and Human Security
Africa
Asia
Australia and New Zealand
Europe
Latin America
North America
     United States
Polar Regions (Arctic and Antarctic)
Small Islands
Global Tipping Points
Six Degrees: Our Future on a Hotter Planet
     1 ^oC Warmer World
     2 ^oC Warmer World
     3 ^oC Warmer World
     4 ^oC Warmer World
     5 ^oC Warmer World
     6 ^oC Warmer World

• Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (2007)
• America's Climate Choices: Panel on Advancing the Science of Climate Change; National Research Council (2010)
• Global Climate Change: Impacts in the United States; U.S. Global Change Research Program (2009)
• Six Degrees: Our Future on a Hotter Planet by Mark Lynas (2008)

• Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases.
• A global assessment of data since 1970 has shown it is likely that anthropogenic warming has had a discernible influence on many physical and biological systems.
• Other effects of regional climate changes on natural and human environments are emerging, although many are difficult to discern due to adaptation and non-climatic drivers.
• More specific information is now available across a wide range of systems and sectors concerning the nature of future impacts, including for some fields not covered in previous assessments.
• Magnitudes of impact can now be estimated more systematically for a range of possible increases in global average temperature.
• Impacts due to altered frequencies and intensities of extreme weather, climate and sea-level events are very likely to change.
• Some large-scale climate events have the potential to cause very large impacts, especially after the 21st century.
• Impacts of climate change will vary regionally but, aggregated and discounted to the present, they are very likely to impose net annual costs which will increase over time as global temperatures increase.

Fig. 1: Locations of significant changes in data series of physical systems (snow, ice and frozen ground; hydrology; and coastal processes) and biological systems (terrestrial, marine, and freshwater biological systems), are shown together with surface air temperature changes over the period 1970-2004.

Figure 2 (IPCC, 2007) shows the key impacts of climate change as global average temperature rises toward 5 ^oC.

Fig. 2: Key Impacts vs Increasing Global T

Figure 3 (IPCC, 2007) shows the possible impacts of climate change due to changes in extreme weather and climate events.

Fig. 3: Impacts of climate change due to changes in extreme weather & climate events

Next: Sea Level Rise & the Coastal Environment

• Introduction
• The Scientific Consensus
• Determining the Climate Record
• Impact of Greenhouse Gases
• Climate Change: The Smoking Gun for Humans
• Natural Causes of Climate Change
• Global Cooling?
• Climate Models & Accuracy
• Modern Day Climate Change
• Impacts of Climate Change
• The Global Warming Denial Machine
• Reasons for the Misinformation
• How to Talk to a Conservative about Climate Change
• Summary of Key Points
• Suggested Reading
• Works Cited

Last updated: 06/05/10