During the Nor’easter storm of December 1992, flooding and strong winds hit the northeastern U.S. with a vengeance causing an almost complete shut down of New York’s subway system. The storm provided a “wake up call” to the city that their public transportation system was vulnerable to severe weather events.

Because of the growing challenges caused by climate changes and the threat of global warming, scientists and policymakers all over the United States have joined forces to participate in the United States National Assessment on the Potential Consequences of Climate Variability and Change, or the “National Assessment” for short.

The National Assessment presently consists of sixteen ongoing regional projects. For each of the regional studies, teams of scientists, resource planners and other stakeholders assemble to assess their region’s most critical vulnerabilities in areas such as agricultural productivity, coastal areas, water resources, forests, and human health. In addition to looking at potential impacts, the teams also identified strategies that can be used to adapt and respond to climate changes. “The goal of the assessment is to provide the information for communities as well as activities to prepare and adapt to the changes in climate that are starting to emerge,” says Michael MacCracken, who heads the national office helping to coordinate the regional and national assessment teams.

The research activities being conducted by the National Assessment teams in the Metropolitan East Coast and the Great Plains region provide good examples of how information is helping the United States prepare for future climate changes.

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The data used in this study are available in one or more of NASA's Earth Science Data Centers.

Cynthia Rosenzweig, a researcher at NASA's Goddard Institute for Space Studies, is a member of the Metropolitan East Coast regional study, which is made up of the 31-county region that comprises the New York City metropolitan area. “We are looking at how people, places, and decision mechanisms of the city respond to climate change and variability as well as to each other,” says Rosenzweig. Her team examined urbanization with city planners, the affects of climate change on human health with the New York City Department of Health, sea level rise with the U.S. Army Corps of Engineers, and wetlands with local environmental groups.

Climate researchers work closely with city planners in New York City to investigate the influence of the “urban heat island” effect on the city, which occurs because asphalt and concrete absorb and retain more heat than vegetation, causing cities to be warmer than surrounding areas. Using satellite data, scientists measure the temperature of the city and can, for example, indicate to city planners where construction of a new park or preserving a forest area would help to cool parts of the city.
 

As another example, the results of scientific studies indicate that as the city’s surface temperature rises, there will be an increase in levels of smog, which can lead to public health and environmental concerns. Researchers have found that the impact of ground-level ozone are likely to become an increasing concern over the coming decades. By evaluating the current state of the atmosphere, the team can make better predictions about how future air quality will affect respiratory health and governments can take actions to help limit pollution, according to Rosenzweig.

Climate change can also affect coastal regions. Sea-level has risen in the New York areas by between 9 and 15 inches over the last 100 years over the region. This observed rise is likely due to both glacial retreat and the warming trend during the 20th century. As sea level continues to rise, there is an increasing threat of more damaging storm surges and an increase in the frequency of 100-year flood events, which could be occurring as often as every 4 years by the year 2080 if projections are correct. The U.S. Army Corps of Engineers in conjunction with hydrologists and oceanographers annually estimate future beach erosion rates due to sea-level rise. Rates of beach erosion are expected to double or even triple in the region by the 2020s. This information is used to predict the effects of coastal storms. The Corps' annual estimates help hydrologists plan effective strategies to try to protect the shore and property. Hydrologists are also concerned that rising sea-levels will raise the salt level, which would cause problems for wildlife and some well-based water systems.
 

Sea-level rise associated with global climate changes not only brings a significant risk to the coast, but also to the coastal wetlands in the region. By analyzing aerial photography and satellite images, researchers can reconstruct how New York's coastal wetlands have evolved over the past 20 years. This information can help scientists predict whether wetland areas will grow or shrink due to climate changes and help local government planners develop policies and preservation practices to protect New York's wetlands.

Based on the research done to contribute to the National Assessment, Rosenzweig says that city agencies will begin to have the information needed to make better decisions that can help limit future problems affecting public health, coastal erosion, water supply and coastal wetlands.

 Surge of the leafy spurge
 Adapting to Global Climate Change

When the leafy spurge, a weed native to Asia, invaded the Great Plains region choking crops and making the cattle that ate it sick, farmers knew that something had to be done to stop the spread of this aggressive weed. George Seielstad, an Earth system scientist at the University of North Dakota, is leader of the Northern Great Plains regional assessment study that has been examining the consequences of climate change for agriculture, forests, grasslands, and water resources. Seielstad and his team analyzed the situation facing North Dakota, South Dakota, Wyoming, Montana, and Idaho as part of the National Assessment.

The leafy spurge is not grazed or limited by predators in the United States, grows quickly (spreading out several feet a year), and has seeds that can remain in the soil for up to seven years. These attributes make the leafy spurge hard to control and eradicate. Scientists turned to satellites for help.

The biggest problem was distinguishing the crops from the weeds in the remote sensing imagery. Using Landsat satellite data, scientists identified areas where leafy spurge infiltrated fields by comparing satellite images. Leafy spurge reflected a very different signal back to the satellite than the signal from fields without the weed. Once the scientists knew where the leafy spurge was present, they could plan an attack.
 

There is a root-boring beetle from Europe that feeds on the leafy spurge, which benefits the crops as well as the environment. The beetle has been imported to spurge-infested areas to solve the problem. “Finding natural predators like the root-boring beetle are neat tools that are environmentally sound and help address problems that are raised by invasive species and are amplified by climate change,” says Seielstad. “We need more of these types of win-win solutions.”
 

One of the most effective means for communicating the results of this study was for Seielstad to personally talk with farmers about the potential crop dangers in their future. “We showed farmers climate data that explained the conditions over the last 100 years,” says Seielstad. “Also, we were able to gather valuable information about the region's soil.” As a result of combining these two factors, Seielstad and his team made an impression on the farmers. “We showed farmers how they could save money on fertilizer by proving to them that their soil had plenty of nitrogen,” says Seielstad. “One husband and wife team discovered that, given the current climatic conditions, it would be more beneficial for them to destroy their crop this year in order to protect the nutrients in the soil for a better crop next year.”

MacCracken stresses that society is making a lot of choices right now that will determine how we are going to be affected by future climate change. “No matter what happens with these international agreements, we are experiencing climate change now, and we will be experiencing it for many decades-we absolutely must get prepared for such changes,” says MacCracken.

For more information:

Metropolitan East Coast Region's website
U.S. National Assessment on the Potential Consequences of Climate Variability and Change website
U.S. Global Change Research Program

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