President Obama’s forceful call for climate action in his inaugural address came after a year when climate change was barely whispered in the presidential campaign but its effects were loud and clear here in the United States and around the world.
As Hurricane Sandy moves out of the region, people in affected areas are beginning to take stock of the damage. Flooding in parts of New Jersey and New York from the storm surge hit record levels. The 13.8-foot surge measured at Battery Park in Lower Manhattan surpassed the all-time record of 11.2 feet set in 1821, flooding the New York subway system and two major commuter tunnels. Along the Eastern Seaboard, an estimated 7.5 million people lost power. Farther inland, blizzard conditions dropped as much as 2 feet of snow as Sandy crashed into arctic air over the Midwest. While early estimates indicate direct damages from the hurricane may be as much as $20 billion, the total economic losses, including losses in consumer and business spending, could be more than twice that amount.
A number of climate change-related factors may well have intensified the storm's impact: higher ocean temperatures, higher sea levels, and an atmospheric traffic jam that may be related to Arctic melting. Hurricane Sandy is also a clear reminder of how vulnerable our homes and infrastructure already are to extreme weather — and this risk is growing.
Hurricane Sandy is a stark reminder of the rising risks of climate change. A number of warming-related factors may well have intensified the storm's impact. Higher ocean temperatures contributed to heavier rainfall. Higher sea levels produced stronger storm surges. New research suggests that Arctic melting may be increasing the risk of the kind of atmospheric traffic jam that drove Sandy inland. While no single weather event can be said to have been directly caused by climate change, our weather now is the product of our changing climate, as increased warming raises the probability of extreme weather events. In highlighting our vulnerabilities to extreme weather, Hurricane Sandy underscores two imperatives: We need to reduce the risks of climate change by reducing our carbon emissions, and we must strengthen our defenses against future impacts that it may be too late to avoid.
Warming increases the amount of moisture in the atmosphere. Globally, the resulting increases in heavy precipitation are well documented. Like Hurricane Irene last year, Sandy carried an unusual amount of moisture, which increased the risk of very heavy precipitation within its path. Much of the warming from climate change occurs in the ocean, and this year’s sea surface temperatures are well above normal. September saw the second highest ocean temperatures on record globally. Sandy spent significant time over uncommonly warm sea surface temperatures – 5 degrees above normal -- boosting the amount of moisture available to rain down on the Northeast U.S.
Sea Level Rise
Recent studies have identified the Northeast U.S. as a “hotspot” of accelerated sea level rise. Over the past 30 years, sea levels in the region have risen four times faster than the global average, increasing the risk of storm surges and flooding. During a storm surge, a matter of inches can mean the difference between safety and extensive flooding. Hurricane Sandy’s storm surge was exacerbated by both the warming-driven sea-level rise and the timing of the lunar cycle. Sandy occurred during the astronomical high tide, which is 2 to 3 inches above a normal high tide. Global sea level has already increased by 4 inches since 1950, creating the equivalent of a fulltime astronomical high tide. In New York, a record storm surge 13 feet above mean low water level flooded parts of lower Manhattan and poured into subway tunnels.
Atlantic Traffic Jam
Hurricane Sandy encountered a “traffic jam” in the North Atlantic, known as a “block” to meteorologists. This block did not allow Sandy to track out to sea like most northeast storms. Meanwhile, a storm associated with some very cold air over the Midwest also ran into this Atlantic traffic jam, resulting in an unusual “hybrid” storm. Recent research has shown that these blocking events and fall cold outbreaks are related to sea ice loss in the Arctic. In short, open water in the arctic helps break down the barrier between high- and mid-latitude weather, which increases the risk of cold outbreaks and blocking events. Hurricane Sandy seems to have tracked into the middle of one of these unusual meanders in the jet stream. While this is an evolving field of research and these conditions could have occurred in the absence of climate change, there is growing evidence that climate change is increasing the risk of extreme atmospheric arrangements.
Hurricane Sandy provides important lessons about our vulnerability to the kinds of extreme weather likely to become more common in a warming world. Our levees, sea walls and other infrastructure were built to cope with the extreme weather risks of the 20th century. Sandy is offering an opportunity to see where we fall short in preparations for the 21st century.
Statement from Elliot Diringer
Executive Vice President, Center for Climate and Energy Solutions
Oct. 29, 2012
Hurricane Sandy is a stark reminder of the rising risks of climate change. While climate change didn’t cause the hurricane, a number of warming-related factors may well be intensifying its impact.
Higher ocean temperatures, in this case 5 degrees above normal, contribute to heavier rainfall. Higher sea level means stronger storm surges. And new research suggests that Arctic melting may be increasing the risk of the kind of atmospheric traffic jam that is driving Sandy inland.
But whatever’s behind it, Sandy clearly highlights our vulnerabilities to extreme weather. We’ve loaded the dice and events we once thought of as rare are becoming more common.
At a minimum, this is another foretaste of what we face in a warming world. It tells us two things: We’d better do all we can to reduce the risks by reducing our carbon emissions, and we’d better strengthen our defenses against future impacts that it’s already too late to avoid.
To get in touch with a C2ES science expert, contact Laura Rehrmann at firstname.lastname@example.org or 703-774-5480.
The Center for Climate and Energy Solutions (C2ES) is an independent nonprofit, nonpartisan organization promoting strong policy and action to address the twin challenges of energy and climate change. Launched in November 2011, C2ES is the successor to the Pew Center on Global Climate Change.
I recently replied to ta question on the National Journal blog, "How is the absence of discussion about global warming going to affect our ability to do something about it?"
You can read more on the original blog post and other responses at the National Journal.
Here is my response:
A report released this week by two senior members of Congress notes that the unusual number of extreme weather events in 2012 has cost the country billions of dollars and that the unusual frequency of these events is consistent with what scientists have predicted from climate change.
The staff report, “Going to Extremes: Climate Change and the Increasing Risk of Weather Disasters” is from the offices of Reps. Edward Markey (D-MA) and Henry Waxman (D-CA), the prime movers behind the last attempt at significant climate legislation. It cites information from a variety of sources, including NOAA, the news media and the private sector to show how rising weather risk costs real money.
Their report comes a week after Congress headed home for the elections having accomplished very little to address climate change. Nearly half the bills introduced by the current Congress would block or hinder climate action, though none of these have been enacted into law.
The U.S. Drought Monitor shows the extent of current drought conditions.
Click on the map above to go to the drought monitor site with a full report and statistics.
Drought and Climate Change
Recent U.S. droughts have been the most expansive in decades. At the peak of the 2012 drought, an astounding 81 percent of the contiguous United States was under at least abnormally dry conditions, resulting in an estimated $30 billion in damages. Climate change increases the odds of worsening drought in many regions of the U.S. and the world in the decades ahead.
Global warming will increase the risk of drought in some regions, particularly in the Southwest United States. Even in regions that may not see changes in precipitation, warmer temperatures can increase water demands and evaporation, putting greater stress on water supplies.
Estimates of future changes in seasonal or annual precipitation in a particular location are subject to considerable uncertainty; more so than estimates of future warming. However, scientists are more confident that at the global scale, relatively wet places such as the tropics and the high latitudes will get wetter, while relatively dry places in the subtropics (where most of the world’s deserts are located) will become drier.
When droughts do occur, warmer temperatures can amplify their impacts. Droughts can persist through a “positive feedback,” where very dry soils and diminished plant cover can further suppress rainfall in an already dry area. Increased temperatures enhance evaporation from soils, making a periodic occurrence of drought worse than it would be under cooler conditions.
Threats to the U.S.
The United States is historically susceptible to drought. Paleoclimate studies show major droughts in the distant past, while some more recent dry periods are still within living memory, such as the Dust Bowl of the 1930s or the drought of the 1950s. These historic examples serve as guideposts to highlight our vulnerabilities to drought as we move into a warmer, and in some places, drier future.
Recent U.S. droughts have been the most expansive in decades. For example, in 2011, Texas experienced its driest 12 months ever. At one point, 80 percent of the state was rated at an “exceptional” level of drought. At the peak of the 2012 drought, an astounding 81 percent of the contiguous United States was under at least abnormally dry conditions. Severe drought can affect:
- Agriculture: Droughts affect livestock and crops, including cornerstone commodities like corn, soybeans and wheat. At the height of the 2012 drought, the U.S. Department of Agriculture declared a natural disaster over 2,245 counties, 71 percent of the United States.
- Transportation: Recent droughts have had major impacts on water levels on the Mississippi River and the ability to move goods along the river. Transport barges need at least nine feet of water, and to maintain this level, the U.S. Army Corps of Engineers had to blast, dredge, and clear obstructions on a key stretch between St. Louis, Mo., And Cairo, Ill.
- Wildfires: In the Southwest, drought conditions and record heat have fueled damaging and sometimes deadly wildfires in Arizona, Colorado and New Mexico. Millions of forested acres and thousands of homes have been lost over the past decade due to fires thriving in dry, stressed forest environments and because of the proximity of communities to fire-prone forests.
- Energy: Droughts can raise concerns about the reliability of electricity production from plants that require cooling water to maintain safe operations. When heat waves coincide with droughts, electricity demands can grow, compounding stress on the grid.
Potential Global Problems
In recent years, droughts have struck several major breadbasket regions simultaneously, adding to food price instability. In countries already facing reduced food security, cost spikes can lead to social unrest, migration, and famine. Several price spikes have occurred over the last decade, often connected to crop failures or poor yield. During the 2007-2008 crisis, the Food and Agriculture Organization of the United Nations estimated that high food prices increased the number of chronically hungry people in the word by 75 million.
How to Build Resilience
Governments and businesses must identify the vulnerabilities that droughts expose and take steps to improve resilience. Actions like using water more efficiently and developing more drought-resistant crops will help prepare us for both future droughts and climate change. These steps will be most effective if they are combined with reductions in greenhouse gases that can minimize the ultimate magnitude of climate change.
To Learn More
As with any single event, Hurricane Isaac doesn’t tell us anything about whether hurricanes are getting worse due to climate change. But Isaac’s impacts should be examined to teach us about our vulnerabilities to the types of extreme events scientists tell us climate change will make more common.
The loss of Arctic sea ice is progressing more rapidly and clearly than just about any other indicator of global climate change. As I’ve discussed previously, the minimum summer sea ice extent (i.e. the two-dimensional area of the floating ice cap) set new record lows in 2002, 2005 and 2007. Similarly, the total volume of sea ice set record lows in 2007, 2010 and 2011. For the first time since 2007, both the sea ice extent and volume have set new record lows in the same year (see figures). And what’s more, they did it with weeks remaining in the melt season, which usually ends in mid-September. So the records have been broken this year, but we don’t know yet just how low the extent and volume will go.