Climate change is already negatively affecting every region in the United States and the future looks even more dismal if coordinated mitigation and adaptation efforts are not immediately aggressively pursued, according to the third U.S. National Climate Assessment report released Tuesday.
“Climate change, once considered an issue for a distant future, has moved firmly into the present,” notes the massive NCA report.
“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.”
The report adds evidence of human-induced climate change continues to strengthen and that impacts are increasing across the nation. The report says Americans are already noticing the results of climate change, from longer and hotter summers to shorter and warmer winters. Rain falls in heavier downpours, there is more flooding, earlier snow melt, more severe wildfires and less summer sea ice in the Arctic.
“Scientists who study climate change confirm that these observations are consistent with significant changes in Earth’s climatic trends,” says the report that was prepared by hundreds of scientists for the U.S. government.
“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.”
The climatic changes are triggering wide-ranging impacts in every region of the U.S. and throughout the nation’s economy, the report says, adding that while some of the changes can be positive over the short run, most are detrimental since American society and its infrastructure was not designed for the rapidly-changing climate now being experienced.
The report analyses impacts on human health, water, energy, transportation, agriculture, forests, and ecosystems. It also assesses impacts on the country’s eight major regions.
“What is new over the last decade is that we know with increasing certainty that climate change is happening now,” the report says. “While scientists continue to refine projections of the future, observations unequivocally show that climate is changing and that the warming of the past 50 years is primarily due to human-induced emissions of heat-trapping gases. These emissions come mainly from burning coal, oil, and gas, with additional contributions from forest clearing and some agricultural practices.”
Noting that the climate is projected to continue to change over this century and beyond, the report says there is still time to act to limit the amount of change and its damaging impacts.
The report says U.S. average temperature has increased by 1.3°F to 1.9°F since 1895, with the most recent decade being the nation’s and the world’s hottest on record.
Temperatures are projected to rise another 2°F to 4°F in most areas of the U.S. over the next few decades. The report says 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, while a higher emissions scenario assuming continued increases in emissions, predominantly from fossil fuel combustion, would result in a 5°F to 10°F rise.
Many scientists suggest that the safe and manageable level of global temperature rise due to climate change should not exceed 3.6 °F (2°C) above pre-industrial levels.
“Climate change poses a major challenge to U.S. agriculture because of the critical dependence of agricultural systems on climate,” the report says.
“The United States produces nearly $330 billion per year in agricultural commodities. This productivity is vulnerable to direct impacts on crops and livestock from changing climate conditions and extreme weather events and indirect impacts through increasing pressures from pests and pathogens.”
“Climate change will also alter the stability of food supplies and create new food security challenges for the United States as the world seeks to feed nine billion people by 2050.”
Water quality and quantity are already being affected by climate change, the report says, adding changes in precipitation and runoff, combined with changes in consumption and withdrawal, have reduced surface and groundwater supplies and increasing the likelihood of water shortages for many uses.
The report adds that climate change affects human health in many ways.
“Increasingly frequent and intense heat events lead to more heat-related illnesses and deaths and, over time, worsen drought and wildfire risks, and intensify air pollution,” the report says.
“Increasingly frequent extreme precipitation and associated flooding can lead to injuries and increases in waterborne disease. Rising sea surface temperatures have been linked with increasing levels and ranges of diseases. Rising sea levels intensify coastal flooding and storm surge, and thus exacerbate threats to public safety during storms.”
The report says that Americans face choices as the impacts of climate change are becoming more prevalent. It adds that some additional climate change impacts are now unavoidable because of past emissions of long-lived heat-trapping gases.
“The amount of future climate change, however, will still largely be determined by choices society makes about emissions. Lower emissions of heat-trapping gases and particles mean less future warming and less-severe impacts; higher emissions mean more warming and more severe impacts.”
The report may give President Barack Obama more power to deal with climate change, the environment and energy issues through administrative amendments during his last 2.5 years in office. On Tuesday, the White House issued a media release saying the report underscores “the need for urgent action to combat the threats from climate change, protect American citizens and communities today, and build a sustainable future for our kids and grandkids.”
Lou Leonard, the World Wildlife Fund’s vice president for climate change, said the report provides a pathway for Americans to choose a more beneficial future.
“We need to use this practical report as a guidebook for preparing local communities for extreme weather and other climate impacts,” Leonard said. “At the same time, we need to transform the way we produce and use energy, leaving dirty coal, oil and gas behind. There is no time to lose.”
Sierra Club executive director Michael Brune applauded the report and urged the Obama administration to promote clean energy solutions like wind and solar power. “We can create good American jobs and power homes and businesses nationwide without polluting our air, water, or climate,” Brune said.
Image Credit: Map showing consecutive dry days from NCA report website