Recognition that climate could change on human timescales made climate processes much more interesting research topics. It also spurred political interest. It had been known since that humans were increasing the amount of heat-trapping greenhouse gases in the atmosphere. Would this warm the climate noticeably? Scientists also knew that human emissions of aerosols could cool the Earth. Which effect would dominate? A study by the U. National Academy of Science said, in effect, "We don't know.
Give us money for research. They had found "no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible. Declining planetary funding and growing scientific interest in the Earth's climate caused planetary scientists to start studying the Earth.
It was closer, and much less expensive, to do research on. And NASA followed suit, starting to plan for an Earth observing system aimed at questions of "global change. NASA developed the technology and funded the science. At the same time, a multi-agency effort called the Global Change Research Program was also taking form.
NASA's role in that larger U. Approved in the fiscal year budget, the resulting Earth Observing System would be the agency's primary contribution to American climate science. Fast forward to , and NASA had 17 space missions collecting climate data. NASA also sponsors field experiments to provide "ground truth" data to check space instrument performance and to develop new measurement techniques.
Once the growing season ends, shorter, milder winters fail to kill dormant insects, increasing the risk of large, damaging infestations in subsequent seasons. In some ecosystems, maximum daily temperatures might climb beyond the tolerance of indigenous plant or animal. To survive the extreme temperatures, both marine and land-based plants and animals have started to migrate towards the poles.
Those species, and in some cases, entire ecosystems, that cannot quickly migrate or adapt, face extinction. The IPCC estimates that percent of plant and animal species will be at risk of extinction if temperatures climb more than 1. The changes to weather and ecosystems will also affect people more directly. Hardest hit will be those living in low-lying coastal areas, and residents of poorer countries who do not have the resources to adapt to changes in temperature extremes and water resources.
As tropical temperature zones expand, the reach of some infectious diseases, such as malaria, will change. More intense rains and hurricanes and rising sea levels will lead to more severe flooding and potential loss of property and life.
One inevitable consequence of global warming is sea-level rise. Intense droughts can lead to an increase in malnutrition. On a longer time scale, fresh water will become scarcer, especially during the summer, as mountain glaciers disappear, particularly in Asia and parts of North America. For example, as long as the rise in global average temperature stays below 3 degrees Celsius, some models predict that global food production could increase because of the longer growing season at mid- to high-latitudes, provided adequate water resources are available.
The same small change in temperature, however, would reduce food production at lower latitudes, where many countries already face food shortages. On balance, most research suggests that the negative impacts of a changing climate far outweigh the positive impacts.
Current civilization—agriculture and population distribution—has developed based on the current climate. The more the climate changes, and the more rapidly it changes, the greater the cost of adaptation.
Ultimately, global warming will impact life on Earth in many ways, but the extent of the change is largely up to us. Scientists have shown that human emissions of greenhouse gases are pushing global temperatures up, and many aspects of climate are responding to the warming in the way that scientists predicted they would.
This offers hope. Since people are causing global warming, people can mitigate global warming, if they act in time. Greenhouse gases are long-lived, so the planet will continue to warm and changes will continue to happen far into the future, but the degree to which global warming changes life on Earth depends on our decisions now. Atmosphere Heat Land Water. EO Explorer. At the time of publication, it represented the best available science. What is Global Warming?
References and Related Resources. Global Warming Throughout its long history, Earth has warmed and cooled time and again. The enhanced greenhouse effect What has scientists concerned now is that over the past years, humans have been artificially raising the concentration of greenhouse gases in the atmosphere at an ever-increasing rate, mostly by burning fossil fuels, but also from cutting down carbon-absorbing forests.
Is Current Warming Natural? Climate Feedbacks Greenhouse gases are only part of the story when it comes to global warming. Snow and ice Perhaps the most well known feedback comes from melting snow and ice in the Northern Hemisphere. Water Vapor The largest feedback is water vapor. Clouds Closely related to the water vapor feedback is the cloud feedback.
Emission Scenarios Scientists predict the range of likely temperature increase by running many possible future scenarios through climate models. Changing Weather For most places, global warming will result in more frequent hot days and fewer cool days, with the greatest warming occurring over land. Impacting Ecosystems More importantly, perhaps, global warming is already putting pressure on ecosystems, the plants and animals that co-exist in a particular climate zone, both on land and in the ocean.
Impacting People The changes to weather and ecosystems will also affect people more directly. References Anthes, R.
Bulletin of the American Meteorological Society, Accessed April 15, Arctic Council. Arctic Climate Impact Assessment Report. Accessed March 22, Balachandran, N. Effects of solar cycle variability on the lower stratosphere and the troposphere. Journal of Geophysical Research, D22 , 27, , Bender, M. Science, , Bonan, G. Cazenave, A. How fast are the ice sheets melting?
Clement, A. Dessler, A. Water-vapor climate feedback inferred from climate fluctuations, Geophysical Research Letters, 35, L Emanuel, K. Increasing destructiveness of tropical cyclones over the past 30 years. Nature, , Foucal, P. Hansen, J. Climate Dynamics, 29 7 , Intergovernmental Panel on Climate Change. Joint Science Academies.
June Jouzel, J. Science , , Labitzke, K. The global signal of the year solar cycle in the stratosphere: observations and models. Journal of Atmospheric and Solar-Terrestrial Physics, 64 2 , Lau, K. Detecting trends in tropical rainfall characteristics, International Journal of Climatology, Lean, J. Geophysical Research Letters, 36, L How natural and anthropogenic influences alter global and regional surface temperatures: to Geophysical Research Letters, 35 Luthcke, S. Recent Greenland ice mass loss by drainage system from satellite gravity observations.
Mann, M. Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia. Proceedings of the National Academy of Sciences, 36 , Manvendra K. Dubey, Petr Chylek, Charlie S. Global Warming and the Next Ice Age.
Bulletin of the American Meteorological Society, 89 12 , McGranahan, G. Balk and B. The rising tide: assessing the risks of climate change and human settlements in low elevation coastal zones. Millennium Ecosystem Assessment, Ecosystems and Human Well-being: Synthesis. Island Press, Washington, DC. Oren, R. Soil fertility limits carbon sequestration by forest ecosystems in a CO2-enriched atmosphere.
Ramanathan, V. On avoiding dangerous anthropogenic interference with the climate system: Formidable challenges ahead. Proceedings of the National Academy of Sciences, 38 , Rind, D. Journal of Geophysical Research, , D Robock, A. Benefits, risks, and costs of stratospheric geoengineering. Sabine, C. Schimel, D. Here, we answer six questions to help you understand NASA's global surface temperature analysis. Katherine Calvin will serve the agency in dual roles as chief scientist and senior climate advisor.
The 3D real-time visualization tool lets users track NASA satellites as well as the vital Earth science data they provide. Recent upgrades make for an even more fascinating experience. NASA is participating in the 26th U. Get the schedule of events where the agency will be involved. Sea ice plays an important role in regulating our climate. Here are five facts to help you better understand Arctic sea ice.
As satellites collect larger and larger amounts of data, engineers and researchers are implementing solutions to manage these huge increases. Climate change is making droughts more frequent, severe, and pervasive. NASA satellites provide data about water availability to the U. Drought Monitor, which helps farmers prepare for drought, determining where and what to feed their livestock.
Climate change is impacting agriculture in a number of ways.
0コメント