Local Climate Changes
Over the last century, temperatures in Albany, New York, have warmed by more than 1°F, and precipitation throughout the state has increased by up to 20%.
Over the next century, New York's climate may change even more. Based on projections given by the Intergovernmental Panel on Climate Change and results from the United Kingdom Hadley Centre's climate model (HadCM2), a model that has accounted for both greenhouse gases and aerosols, by 2100 temperatures in New York could increase about 4°F in winter and spring, and slightly more in summer and fall (with a range of 2-8°F). Precipitation is projected to increase by 10-20% (with a range of 0-40%), with slightly less change in spring and slightly more in winter.
The amount of precipitation on extreme wet (or snowy) days is likely to increase, but changes in the lengths of wet or dry spells are not clear. The frequency of extreme hot days in summer is expected to increase along with the general warming trend. It is not clear how severe storms such as hurricanes would change.
Climate Change Impacts
Global climate change poses risks to human health and to terrestrial and aquatic ecosystems. Important economic resources such as agriculture, forestry, fisheries, and water resources also may be affected. Warmer temperatures, more severe droughts and floods, and sea level rise could have a wide range of impacts. All these stresses can add to existing stresses on resources caused by other influences such as population growth, land-use changes, and pollution.
Similar temperature changes have occurred in the past, but the previous changes took place over centuries or millennia instead of decades. The ability of some plants and animals to migrate and adapt appears to be much slower than the predicted rate of climate change.
Human Health
Higher temperatures and increased frequency of heat waves may increase the number of heat-related deaths and the incidence of heat-related illnesses. New York, with its irregular, intense heat waves, could be especially susceptible.
In New York City, one study projects that a 1°F warming could more than double heat-related deaths during a typical summer, from about 300 today to over 700 (although increased air conditioning use may not have been fully accounted for). Decreases in winter mortality probably would be less than the summer mortality increases if the climate warms. The elderly, particularly those living alone, are at greatest risk.
There is concern that climate change could increase concentrations of ground-level ozone. For example, high temperatures, strong sunlight, and stable air masses tend to increase urban ozone levels. Air pollution also is made worse by increases in natural hydrocarbons emissions during hot weather. If a warmed climate causes increased use of air conditioners, air pollutant emissions from power plants also will increase.
A 4°F warming in New York City, with no other change in weather or emissions, would increase concentrations of ground-level ozone, a major component of smog, by 4%. Current ozone concentrations exceed the national health standards in many urban areas, especially New York City and Long Island. Ground-level ozone has been shown to aggravate existing respiratory illnesses such as asthma, reduce lung function, and induce respiratory inflammation. In addition, ambient ozone reduces agricultural crop yields and impairs ecosystem health.
Warming and other climate changes may expand the habitat and infectivity of disease-carrying insects, increasing the potential for transmission of diseases such as malaria and dengue ("break bone") fever. Mosquitoes flourish in some areas around New York City. Some can carry malaria, while others can carry Eastern equine encephalitis, which can be lethal or cause neurological damage. Lyme disease, which is carried by ticks, has increased in New York. If conditions become warmer and wetter, mosquito and tick populations could increase, thereby increasing the risk of transmission of these diseases.
In addition, warmer seas could contribute to the increased intensity, duration, and extent of harmful algal blooms. These blooms damage habitat and shellfish nurseries, can be toxic to humans, and can carry bacteria, like those causing cholera. Brown algal tides already are prevalent in the Atlantic. Warmer ocean waters could increase their occurrence and persistence.
Forests
Trees and forests are adapted to specific climate conditions, and as climate warms, forests will change. This would include changes in species, geographic extent, and health and productivity. If conditions also become drier, the current range of forests might be reduced and replaced by grasslands and pasture. Even a warmer and wetter climate would lead to changes; trees that are better adapted to warmer conditions, such as southern pines, would prevail. Forests could, under these conditions, become more dense. These changes might occur during the lifetimes of today's children, particularly if they are accelerated by other stresses such as fire, pests, and diseases. Some of these stresses would themselves be worsened by a warmer and drier climate.
With changes in climate, the extent of forested areas in New York could change little or could decline by as much as 10-25%. However, the types of trees dominating New York forests are likely to change. The predominant maple, beech, and birch forests found in northern and western New York would retreat northward. The brilliant autumn foliage of the maples eventually could give way to forests dominated by oaks, ash, and pines. Across the state, as much as 50-70% of the maple forests could be lost. As a result, the character of heavily visited areas such as the Adirondacks may change.
Coastal Areas
Along much of New York's coast, sea level already is rising 10 inches per century, and it is likely to rise another 22 inches by 2100. Sea level rise can lead to flooding of low-lying areas, loss of coastal wetlands, erosion of beaches, saltwater contamination of drinking water, and decreased longevity of low-lying roads, causeways, and bridges. In addition, sea level rise could increase the vulnerability of coastal areas to storms and associated flooding.
New York has one of the most urbanized coastlines in the United States. Over 20 million people use New York's beaches and coastal regions for recreation each year. New York has been successful at preventing major permanent losses of its beaches and urban coastline, but sites such as Long Island continue to suffer from chronic beach erosion. Long Island's south shore, which is made up of barrier islands, barrier spits, ponds, and sand beaches, could suffer extensive damage from sea level rise and coastal storms.
Protecting New York's coast would require significant resources and planning. For example, Manhattan's 29-mile coast probably could be protected by raising existing bulkheads and sea walls at a cumulative cost of $30-$140 million for a 1-3 foot rise in sea level. The costs of raising existing bulkheads already have begun to accrue, and they could continue throughout the next century.
Water Resources
Water resources are affected by changes in precipitation as well as by temperature, humidity, wind, and sunshine. Changes in streamflow tend to magnify changes in precipitation. Water resources in drier climates tend to be more sensitive to climate changes. Because evaporation is likely to increase with warmer climate, it could result in lower river flow and lower lake levels, particularly in the summer. In addition, more intense precipitation could increase flooding. If streamflow and lake levels drop, groundwater also could be reduced.
Scientists are unable to predict whether streamflow in New York would rise or fall on average. However, there could be higher streamflow in the winter and lower streamflow in spring and summer. Changes in the seasonality of streamflow (more in winter, less in summer) would make it difficult for the water supply systems in cities like New York to meet current demands reliably. In addition, higher temperatures and lower flow could reduce water quality in New York's rivers and streams.
Increased evaporation probably would reduce the average levels of Lakes Erie and Ontario by up to a foot. These changes would exacerbate water quality problems in those lakes, as well as in the numerous smaller lakes in the St. Lawrence River basin. Lower water levels in Lakes Erie and Ontario would reduce flood damages, but shore erosion would increase from wind and rain. The ice-free season for the St. Lawrence Seaway would be longer, with positive benefits to navigation.
Agriculture
The mix of crop and livestock production in a state is influenced by climatic conditions and water availability. As climate warms, production patterns will shift northward. Increases in climate variability could make adaptation by farmers more difficult. Warmer climates and less soil moisture due to increased evaporation may increase the need for irrigation. However, these same conditions could decrease water supplies, which also may be needed by natural ecosystems, urban populations, and other economic sectors.
Understandably, most studies have not fully accounted for changes in climate variability, water availability, and imperfect responses by farmers to changing climate. Including these factors could substantially change modeling results. Analyses based on changes in average climate and which assume farmers effectively adapt suggest that aggregate U.S. food production will not be harmed, although there may be significant regional changes.
In New York, agriculture is about a $3 billion a year industry, two-thirds of which comes from dairy livestock. The major crops in the state are hay, corn, and silage. Changes in New York yields could range from 0 to -40%. Climate change could lower production and farm income, but total acres farmed most likely would remain constant. Although very little land is currently irrigated, irrigated acreage probably would increase with climate change.
Ecosystems
The ecosystems of New York are quite diverse, ranging from coastal marshes to mountain forests. These ecosystems would be affected by everything from sea level rise to changes in fires and pest outbreaks. Sea level rise could alter food availability for wading birds and other animals in the coastal areas because of loss of wetlands. In higher elevation wetlands, climate warming could reduce streamflow and lake levels, which would result in losses of vegetation such as cranberries. Brook trout habitat and fisheries, which require cold temperatures, could be lost entirely throughout New York, and most of the habitat for brown trout could be lost.
Adirondack State Park is the largest single forested area east of the Mississippi, consisting of 6 million acres, 2.6 million of which are a forest preserve. The park represents one of the most significant hardwood ecosystems in the world. A warmer climate could change the types and extent of forests. The migration of species to new locations out of the park could be impeded by economic development around the park.