WASHINGTON — Saying that climate change has “moved firmly into the present,” a federal scientific panel Tuesday released a report cataloging the impacts of such changes, saying some would actually be beneficial “but many more are detrimental.”
The American Southeast and Caribbean region is “exceptionally vulnerable” to rising sea levels, extreme heat events, hurricanes and decreased water resources, the report said. Seven major ports in the region are vulnerable. And residents can expect a significant increase in the number of hot days – defined as 95 degrees or above – as well as decreases in freezing events.
“Large numbers of southeastern cities, roads, railways, ports, airports, oil and gas facilities and water supplies are vulnerable to the impacts of sea level rise,” the report concluded. Among the cities most at risk: Miami; Tampa, Fla.; Charleston, S.C.; New Orleans, and Virginia Beach, Va.
The findings come from the U.S. National Climate Assessment and was the result of a three-year project involving more than 300 experts and top administration officials, including President Obama’s science and technology adviser and the head of the National Oceanic and Atmospheric Administration. The report was called for in Obama’s climate action plan that was launched last year. White House officials are set to discuss the report Tuesday afternoon.
A draft of the report had previously been released, and report authors received more than 4,000 public comments.
Climate-change skeptics already attacked the report. The Cato Institute, a Washington-based libertarian think tank, set out its assessment Monday, saying the report “overly focuses on the supposed negative impacts from climate change while largely dismissing or ignoring the positives from climate change.”
It said the “bias … towards pessimism” has implications for the federal regulatory process because the report is cited as a primary source for the science of climate change for justifying federal regulations.
“Since the [National Climate Assessment] gets it wrong, so does everyone else,” Cato’s authors said.
The report lays out climate-change scenarios that have or may impact different regions and sectors of the economy.
The state-by-state, region-by-region impacts are what White House officials said in a conference call Tuesday could help move the climate-change debate forward. Calling it “actionable science,” White House adviser John Podesta in a conference call Tuesday said that the report will give people information on observed climate changes in their parts of the nation.
“For decades we’ve been collecting the dots on climate change,” added Jerry Melillo, a scientist at the Marine Biological Laboratory who chaired the committee overseeing the report. “Now we are connecting those dots.”
The report on the Southeast and Caribbean itself is 22 pages; reports on each of the regions of the country are available on the National Climate Assessment’s Web site.
In the Southeast and Caribbean, for example, the report notes that the region warmed during the early part of last century, cooled for a few decades and is now warming again. The report says that global sea level rose about 8 inches in the last century and is projected to rise another 1 to 4 feet this century.
As a result, the coastline of Puerto Rico around Rincon is being eroded at a rate of 3.3 feet per year; 56 percent of Puerto Rico’s population lives in coastal communities.
The report zeroed in on southeast Florida, saying that “just inches of sea level rise will impair the capacity of stormwater drainage systems to empty into the ocean,” the report said. That’s led to states and cities employing adaptation strategies -- which can involve building barriers to keep the water out, accommodating the intruding water or retreating.
The report cited the Southeast Florida Regional Compact as an “excellent example” of collaboration among county, state and federal agencies to adapt to changing circumstances.
As for hurricanes, projections suggest that warming will cause tropical storms to be fewer in number globally but stronger in force, with more Category 4 and Category 5 storms.
In Louisiana, a state highway used for delivering oil and gas resources is sinking at the same time sea level is rising, resulting in more frequent and more severe flooding during high tides and storms, the report said.
Throughout the region, freshwater supplies from rivers, streams and groundwater sources are at risk from accelerated saltwater intrusions due to higher sea levels.
In the Midwest, the report said longer growing seasons and rising carbon dioxide levels will increase yields of some crops, although those benefits will be progressively offset by extreme weather events.
In the Great Plains, rising temperatures are leading to increased demands for water and energy. It could constrain development and increase competition for water among communities, agriculture and energy production.
In the Southwest, which in the report included California, snowpack and streamflow amounts are projected to decline, decreasing surface water supply, threatening the region’s production of specialty crops. In addition, increasing warming, drought and insect outbreaks tied to climate change have increased wildfires and the impact on people and ecosystems.
In the Northwest, changes in snowmelt have already been observed and will continue, reducing the supply of water. The combined impact of increasing wildfires, insect outbreaks and tree diseases have already caused widespread tree deaths “and are virtually certain to cause additional forest mortality by the 2040s and long-term transformation of forest landscapes.”
Not all climate changes are bad, the report concluded. Some, such as a longer growing season in some regions and a longer shipping season on the Great Lakes, “can be beneficial over the short run.”
“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,” the report said.