USGCRP: Climate Change Impacts in the United States

InsightaaS: At dinner recently, a friend asked an environmentally-focused young woman whether colonizing distant planets was the best option for humans whose home planet is rapidly becoming less hospitable. Her answer was that given our environmental record on Earth, she’d hesitate to recommend that we bring our habits to other spheres.

This conversation is clearly speculative, but the issue and consequences are not. A recent report issued by the National Climate Assessment report issued by the US Global Change Research Program provides detailed evidence of climate change and its impacts. This extremely thorough analysis (the work of more than 300 contributors, the full report is 841 pages) paints a clear picture of temperature trends, noting that “The period from 2001 to 2012 was warmer than any previous decade in every region” of the US, and stating that increased global temperatures “have affected and will continue to affect human health, water supply, agriculture, transportation, energy, coastal areas, and many other sectors of society, with increasingly adverse impacts on the American economy and quality of life.” When the analysis turns to response options, we learn that “Especially because of past emissions of long-lived heat-trapping gases, some additional climate change and related impacts are now unavoidable.” The treatment of mitigation and adaptation as response strategies ends with the observation that “choices we make will affect our future and that of future generations.”

Unfortunately, despite the notation in the report that the affects of climate change are more pronounced in the north, there is no analogous Canadian view of this information. Some sections of the report are or should be worrisome to Canadians, though, such as the section that states “in managing water supplies to adapt to a changing climate, the implications of international treaties should be considered in the context of managing the Great Lakes, the Columbia River, and the Colorado River to deal with increased drought risk.” It seems clear that as temperatures rise, the US government will be under pressure from the population to move water from international sources to meet (US) domestic demand.

The report makes the case that “Multiple lines of independent evidence confirm that human activities are the primary cause of the global warming of the past 50 years.” This is an issue of our making; hopefully, an effective solution of our making can be effected before ‘space colonization’ becomes our best option!

Climate change, once considered an issue for a distant future, has moved firmly into the present. Corn producers in Iowa, oyster growers in Washington State, and maple syrup producers in Vermont are all observing climate-related changes that are outside of recent experience. So, too, are coastal planners in Florida, water managers in the arid Southwest, city dwellers from Phoenix to New York, and Native Peoples on tribal lands from Louisiana to Alaska. This National Climate Assessment concludes that the evidence of human-induced climate change continues to strengthen and that impacts are increasing across the country.

Americans are noticing changes all around them. Summers are longer and hotter, and extended periods of unusual heat last longer than any living American has ever experienced. Winters are generally shorter and warmer. Rain comes in heavier downpours. People are seeing changes in the length and severity of seasonal allergies, the plant varieties that thrive in their gardens, and the kinds of birds they see in any particular month in their neighborhoods.

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. Insurance rates are rising in some vulnerable locations, and insurance is no longer available in others. Hotter and drier weather and earlier snow melt mean that wildfires in the West start earlier in the spring, last later into the fall, and burn more acreage. In Arctic Alaska, the summer sea ice that once protected the coasts has receded, and autumn storms now cause more erosion, threatening many communities with relocation.

Scientists who study climate change confirm that these observations are consistent with significant changes in Earth’s climatic trends. Long-term, independent records from weather stations, satellites, ocean buoys, tide gauges, and many other data sources all confirm that our nation, like the rest of the world, is warming. Precipitation patterns are changing, sea level is rising, the oceans are becoming more acidic, and the frequency and intensity of some extreme weather events are increasing. Many lines of independent evidence demonstrate that the rapid warming of the past half-century is due primarily to human activities…

Read the summary and overview: http://nca2014.globalchange.gov/highlights/overview/overview#intro-section