Global Climate Change Impacts in the United States: A State of Knowledge Report of the U.S. Global Climate Research Program
Thomas Karl with Kit Batten
Human-induced climate changes are happening now and are projected to increase. Choices made about emissions now and in the coming years will have far-reaching consequences. The rate and magnitude of future climate change and the resulting impacts depend critically on the amount of global greenhouse gases and atmospheric particles (aerosols). Because we are already committed to significant changes in climate, adaptation strategies will be necessary to help reduce some of the undesirable impacts. Careful planning and regular feedback regarding climate change impacts on ecosystem and social systems will be important input for effective mitigation and adaptation policies.
I reported on Ten Key Findings today:
- Global warming is unequivocal and primarily human-induced
- Climate changes are underway in the United States and are projected to grow
- Widespread climate-related impacts are occurring now and are expected to increase
- Climate change will stress water resources
- Crop and livestock production will be increasingly challenged
- Coastal areas are at increasing risk from sea-level rise, storm surge, and other climate-related stresses
- Threats to human health will increase
- Climate change will interact with many social and environmental stresses
- Thresholds will be crossed, leading to large changes in climate and ecosystems
- Future climate change and its impacts depend on choices made today
Climate Change Spherecast
Dr. Sandy MacDonald
Today Dr MacDonald gave an international spherecast. His presentation on the sphere in Copenhagen was shown simultaneously on spheres in multiple science centers across the U.S. and one in Finland.
Extreme Weather and Climate Events in a Changing Climate: North America including Hawaii, the Caribbean, and the US Pacific Islands
Thomas Karl with Thomas R. Armstrong
Many weather and climate extremes are already changing and their associated impacts are already being felt. New studies have recently emerged that link human-caused increases in greenhouse gases to changes in weather and climate extremes at the scale of a continent.
In the future we expect that:
- Heat waves and heavy downpours are very likely to further increase in frequency and intensity.
- Some areas of North America are likely to have more frequent droughts of greater severity
- Hurricane wind speeds, rainfall intensity, and storm surge levels are likely to increase.
- The strongest cold season storms are likely to become more frequent, with stronger winds and more extreme wave heights.
Current and future impacts depend not only on the changes in extremes, but also on response by social and eco- systems.