Global Warming - Impacts
Introduction
Most experts agree that average global temperatures could rise by 1 to 3,5 degrees Celsius over the next century.
For many people, warmer temperatures might not seem like such a bad idea. But scientists warn us of the possible consequences:
- More severe weather events like droughts, winter storms and tornadoes
- Raising sea level
- Changing clima could alter forests, crop yields, water supplies
- Threating human health
- Harming of birds,fish and so on
- Flooding and erosion in coastal regions
- Our forests and farms would be at greater risk from pests, diseases and fires
- Damage to our water sources
Health
Troughout the world, the prevalence of particular diseases and other threats to human health depend largely on local climate. Extreme temperatures can directly cause the loss of life. Moreover, several serious diseas only appear in warm areas. Finally, warm temperatures can increase air and water pollution, which in turn harm human health.
Extremely hot temperatures increase that people with heart problems are vulnerable because one's cardiovascular system must work harder to keep the body cool during hot weather. Heat exhaustion and some respiratory problems increase.
Higher air temperatures also increase the concentration of onzone at ground level. Ozone damages lung tissue, and causes particular problems for people with asthma and other lung diseases. In much of the nation, a warming of four degrees (F) could increase ozone concentrations by about 5 percent.
Warmer temperatures may increase the number of people who die each year from cold weather. However, in the United States, only 1000 people die from the cold each year, while twice that many die from the heat.
Global warming may also increase the risk of some infectious diseas, particular those diseases that only appear in warm areas. Diseases that are spread by mosquitos and other insects could become more prevalent if warmer temperatures enabled those insects to become established farther north.
In spite of these risks, increased mortality is not an inevitable consequence of global warming. Malaria, for example, is rare in the United States even in warmer regions where the mosquito that transmits the disease is found, because this nation has the ability to rapidly identify and contain outbreaks when they appear.
Water resources
Changing climate is expected to increase both evaporation and precipitation in most areas of the United States. In those areas where evaporation increases more than precipitation, soil will become drier, lake levels will drop, and rivers will carry less water.
Lower river flows and lower lake levels could impair navigation, hydroelectric power generation, and water quality, and reduce the supplies of water available for agricultural, residential and industrial uses.
Warmer temperatures would cause the snow to melt earlier and thus reduce summer supplies even if rainfall increased during the spring. More generally, the tendency for rainfall to be more concentrated in large storms as temperatures rise would tend to increase river flooding, without increasing the amount of water available.
Forests
The projected 2°C warming could shift the ideal range for many North American forests species by about 300km to the north. If the climate changes slowly enough, warmer temperatures may enable the trees to colonize north into areas that are currently too cold , at about the same rate as southern areas became too hot and dry for the species to survive. If the earth warms 2°C in 100 years, however, the species would have to migrate about 2 miles every year.
Trees whose seeds are spread by birds may are able to spread at that rate. But neither trees whos seeds are carried by the wind. Poor soils may also limit the rate at which tree species can spread north. Those, the range over which a particular species is found may tend to be squeezed as southern areas become inhospitably hot. The net result is that some forets may tend to have a less diverse mix of tree species.
Coastel Zones
Sea level is rising more rapidly along the US coast than worldwide. Studies have estimated that along the Gulf and Atlantic coasts, a 30cm rise in sea level is likely by 2050 and could occur as soon as 2025. in next century, a two foot rise is most likely, but a four foot rise is possible. The sea level will probably continue to rise for several centuries, even if global temperatures were stop rising a few decades hence.
Rising sea level inundates wetlands and other low-lying lands, erodes beaches, intensifies flooding, and increases the salinity of rivers, bays, and groundwater tables.
Coastel marshes and swamps are particular vulnerable to rising sea level because they are mostly withhin a few feet of sea level. As the sea rises, the outer boundary of these wetlands will erode, and new wetlands will form inland as previosly dry areas are flooded by the higher water levels. A higher sea level raises the flood level from a storm of given severity. A 3-foot rising sea level (for example) would enable a 15-year storm to flood many areas that today are only flooded by a 100-year storm.
Coastal flooding is also exacerbated by increasing rainfall intensity. Along tidal rivers and in extremely flat areas, floods can caused by storm surges from the sea or by a river surges.
Preguntas frecuentes: Impactos del calentamiento global
¿Cuáles son algunos de los posibles impactos del calentamiento global?
Los científicos advierten sobre varias consecuencias posibles del calentamiento global, incluyendo eventos climáticos más severos (sequías, tormentas invernales, tornados), aumento del nivel del mar, alteraciones en bosques, cultivos y suministros de agua, amenazas a la salud humana, daño a la vida silvestre, inundaciones y erosión en regiones costeras, mayor riesgo de plagas, enfermedades e incendios en bosques y granjas, y daños a fuentes de agua.
¿Cómo afecta el calentamiento global a la salud humana?
El calentamiento global puede afectar la salud humana a través de temperaturas extremas (causando directamente pérdida de vidas y agravando problemas cardíacos), aumento de la contaminación del aire (incrementando la concentración de ozono, dañando el tejido pulmonar), y la posible propagación de enfermedades infecciosas transmitidas por mosquitos y otros insectos a áreas más al norte.
¿Qué se espera que suceda con los recursos hídricos debido al cambio climático?
Se espera que el cambio climático aumente tanto la evaporación como la precipitación en muchas áreas. En las áreas donde la evaporación supera la precipitación, el suelo se secará, los niveles de los lagos disminuirán y los ríos transportarán menos agua. Esto podría afectar la navegación, la generación de energía hidroeléctrica, la calidad del agua y el suministro de agua para diversos usos.
¿Cómo afectará el calentamiento global a los bosques?
Un calentamiento de 2°C podría desplazar el rango ideal para muchas especies forestales de América del Norte unos 300 km hacia el norte. Si el cambio climático es lo suficientemente lento, los árboles podrían colonizar nuevas áreas al norte. Sin embargo, si el calentamiento ocurre rápidamente, las especies podrían no ser capaces de migrar lo suficientemente rápido, lo que podría reducir la diversidad de especies en algunos bosques.
¿Qué consecuencias tendrá el aumento del nivel del mar en las zonas costeras?
El aumento del nivel del mar puede inundar humedales y otras tierras bajas, erosionar playas, intensificar las inundaciones y aumentar la salinidad de los ríos, bahías y aguas subterráneas. Los pantanos costeros son particularmente vulnerables. Además, un nivel del mar más alto aumenta el nivel de inundación de una tormenta de una severidad dada.
¿Cómo afecta el aumento del nivel del mar la salinidad del agua?
El aumento del nivel del mar tiende a aumentar la salinidad tanto del agua superficial como del agua subterránea. Los acuíferos más vulnerables son aquellos que se recargan en áreas que actualmente son de agua dulce, pero que podrían volverse saladas en el futuro.
- Arbeit zitieren
- Friederike Kötter (Autor:in), 2000, Impacts of global warming, München, GRIN Verlag, https://www.hausarbeiten.de/document/100520
