Severe Weather The New Normal

Human Induced Climate Change Experiment

A study mandated by congress highlights the cost of global warming to United States citizens. One of the most significant costs is the impact of more severe weather events.

A LETTER TO THE AMERICAN PEOPLE

Climate change, once considered an issue for a distant future, has moved firmly into the present. This report of the National Climate Assessment and Development Advisory Committee concludes that the evidence for a changing climate has strengthened considerably since the last National Climate Assessment report, written in 2009. Many more impacts of human-caused climate change have now been observed. Corn producers in Iowa, oyster growers in Washington State, and maple syrup producers in Vermont have observed changes in their local climate that are outside of their experience. So, too, have coastal planners from Florida to Maine, water managers in the arid Southwest and parts of the Southeast, and Native Americans on tribal lands across the nation.

Americans are noticing changes all around them. Summers are longer and hotter, and periods of extreme heat last longer than any living American has ever experienced. Winters are generally shorter and warmer. Rain comes in heavier downpours, though in many regions there are longer dry spells in between.

Other changes are even more dramatic. Residents of some coastal cities see their streets flood more regularly during storms and high tides. Inland cities near large rivers also experience more flooding, especially in the Midwest and Northeast. Hotter and drier weather and earlier snow melt mean that wildfires in the West start earlier in the year, last later into the fall, threaten more homes, cause more evacuations, and burn more acreage. In Alaska, the summer sea ice that once protected the coasts has receded, and fall storms now cause more erosion and damage that is severe enough that some communities are already facing relocation.

Scientists studying climate change confirm that these observations are consistent with Earth’s climatic trends. Long-term, independent records from weather stations, satellites, ocean buoys, tide gauges, and many other data sources all confirm the fact that our nation, like the rest of the world, is warming, precipitation patterns are changing, sea level is rising, and some types of extreme weather events are increasing. These and other observed climatic changes are having 26 wide-ranging impacts in every region of our country and most sectors of our economy. Some of these changes can be beneficial, such as longer growing seasons in many regions and a longer shipping season on the Great Lakes. But many more have already proven to be detrimental, largely because society and its infrastructure were designed for the climate of the past, not for the rapidly changing climate of the present or the future.

This National Climate Assessment collects, integrates, and assesses observations and research from around the country, helping to show what is actually happening and what it means for peoples’ lives, livelihoods, and future. This report includes analyses of impacts on seven selected sectors: human health, water, energy, transportation, agriculture, forests, and ecosystems and biodiversity. This report additionally focuses on the interactions among several sectors at the national level. It also assesses key impacts on the regions of the U.S.: Northeast, Southeast and Caribbean, Midwest, Great Plains, Southwest, Northwest, Alaska and the Arctic, Hawaii and the Pacific Islands; as well as coastal areas, oceans, and marine resources. Finally, this report is the first to explicitly assess the current state of adaptation, mitigation, and decision support activities.

STUDY

1. Executive Summary

2. Our Changing Climate

Introduction to Sectors

3. Water Resources

4. Energy Supply and Use

5. Transportation

6. Agriculture

7. Forestry

8. Ecosystems, Biodiversity, and Ecosystem Services

9. Human Health

10. Water, Energy, and Land Use