Climate change is no longer a future threat – it’s a clear and present danger, particularly for California communities, according to the third National Climate Assessment.
The San Francisco Chronicle reports:
Dwindling water for farms, longer fire seasons and coastal flooding of homes and businesses await California as climate change intensifies, according to a federal report released Tuesday that details how global warming is damaging every region of the country.
The third National Climate Assessment, compiled over four years by more than 300 scientists at the direction of Congress, said California’s farm industry, which provides more than half the nation’s fruits, nuts and vegetables, is particularly vulnerable. So are many cities along the coast, including San Francisco, that are already experiencing flooding at high tides as sea levels rise.
Competition for scarce water as the Sierra snowpack diminishes is expected to intensify among cities, farmers and the environment, the report says.
California had its warmest January on record this year. Temperatures nationally are expected to rise 2 to 4 degrees Fahrenheit over the next few decades, on top of a 1.5-degree warming since the late 1800s, most of it since 1970, the report says.
According to the Climate Assessment website:
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.
The observed warming and other climatic changes are triggering wide-ranging impacts in every region of our country and throughout our economy. Some of these changes can be beneficial over the short run, such as a longer growing season in some regions and a longer shipping season on the Great Lakes. But many more are detrimental, largely because our society and its infrastructure were designed for the climate that we have had, not the rapidly changing climate we now have and can expect in the future. In addition, climate change does not occur in isolation. Rather, it is superimposed on other stresses, which combine to create new challenges.
The assessment goes on to say
Reductions in some short-lived human-induced emissions that contribute to warming, such as black carbon (soot) and methane, could reduce some of the projected warming over the next couple of decades, because, unlike carbon dioxide, these gases and particles have relatively short atmospheric lifetimes. The amount of warming projected beyond the next few decades is directly linked to the cumulative global emissions of heat-trapping gases and particles. By the end of this century, a roughly 3°F to 5°F rise is projected under a lower emissions scenario, which would require substantial reductions in emissions (referred to as the “B1 scenario”), and a 5°F to 10°F rise for a higher emissions scenario assuming continued increases in emissions, predominantly from fossil fuel combustion (referred to as the “A2 scenario”).
According to the Chronicle, President Obama
plans to make addressing climate change a major push of his remaining time in office, even as control of the Senate rests with Democrats clinging to seats in the heart of the fossil fuel industry.
The Chronicle provided this quick overview from the report:
Heat: Temperatures have risen since the 1950s in California, Nevada and the Four Corners states faster than at any other time in at least the past 600 years.
Wildfires: From 1970 to 2003, warming temperatures and drier conditions contributed to a 650 percent increase in forest acreage burned in wildfires.
Fire forecast: If greenhouse-gas emissions continue at current levels, annual acreage burned in wildfires in Northern California could double by the end of the century.
Snow: California and other Western states will see a drop in the water content of snow.
Agriculture: Drier weather will lead to less water for agriculture, which accounts for about 80 percent of water usage in the Southwest.
Sea level: A 16-inch rise in sea level on the California coast is expected, threatening the San Francisco and Oakland airports.
View the full report at //nca2014.globalchange.gov.