Global warming is the phenomenon of a gradual increase in the temperature near the earth’s surface. This phenomenon has been observed over the past one or two centuries. This change has disturbed the climatic pattern of the earth 2/1/ · Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to an increase in average global temperatures. This is caused primarily by increases in greenhouse gases such as Carbon Dioxide (CO 2) Paragraph/Article – 6. The challenge before us is to reduce Global warming. Global warming will melt the polarize caps. It is estimated that if all the ice on the earth melts, about feet of water would be added to the surface of all oceans. Satellite pictures have shown that the solar ice has been shrinking by 10 percent per decade since
global warming | Definition, Causes, Effects, Solutions, & Facts | Britannica
Throughout its long history, Earth has warmed and cooled time and again. NASA astronaut photograph ISSE Earth has experienced climate change in the past without help from humanity. But the current small paragraph on global warming warming is occurring much more rapidly than past warming events. These natural causes are still in play today, but their influence is too small or they occur too slowly to explain the rapid warming seen in recent decades.
Based on plausible emission scenarios, average surface temperatures could rise between 2°C and 6°C by the end of the 21st century. Some of this warming will occur even if future greenhouse gas emissions are reduced, because the Earth system has not yet fully adjusted to environmental changes we have already made.
The impact of global warming is far greater than just increasing temperatures. Warming modifies rainfall patterns, amplifies coastal erosion, lengthens the growing season in some regions, melts ice caps and glaciers, and alters the ranges of some infectious diseases.
Some of these changes are already occurring. How can we be certain that human-released greenhouse gases are causing the warming? How much more will the Earth warm?
How will Earth respond? Answering these questions is perhaps the most significant scientific challenge of our time. The global average surface temperature rose 0. Temperatures are certain to go up further. Despite ups and downs from year to year, global average surface temperature is rising.
NASA figure adapted small paragraph on global warming Goddard Institute for Space Studies Surface Temperature Analysis. Roughly 30 percent of incoming sunlight is reflected back into space by bright surfaces like clouds and ice.
Of the remaining 70 percent, most is absorbed by the land and ocean, and the rest is absorbed by the atmosphere. The absorbed solar energy heats our planet. From the surface, this energy travels into the atmosphere where much of it is absorbed by water vapor and long-lived greenhouse gases such as carbon dioxide and methane. They radiate in all directions, small paragraph on global warming. The energy that radiates back toward Earth heats both the lower atmosphere and the surface, enhancing the heating they get from direct sunlight.
This absorption and radiation of heat by the atmosphere—the natural greenhouse effect—is beneficial for life on Earth. 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, small paragraph on global warming, mostly by burning fossil fuels, but also from cutting down carbon-absorbing forests.
Since the Industrial Revolution began in aboutcarbon dioxide levels have increased nearly 38 percent as of and methane levels have increased percent. Increases in concentrations of carbon dioxide top and methane bottom coincided with the start of the Industrial Revolution in about Small paragraph on global warming from Antarctic ice cores green lines combined with direct atmospheric measurements blue lines show the increase of both gases over time.
NASA graphs by Robert Simmon, based on data from the NOAA Paleoclimatology and Earth System Research Laboratory. The atmosphere today contains more greenhouse gas molecules, so more of the infrared energy emitted by the surface ends up being absorbed by the atmosphere. We know small paragraph on global warming past climates because of evidence left in tree rings, layers of ice in glaciers, ocean sediments, coral reefs, and layers of sedimentary rocks, small paragraph on global warming.
The chemical make-up of the ice provides clues to the average global temperature. Earth has cycled between ice ages low points, large negative anomalies and warm interglacials peaks.
NASA graph by Robert Simmon, based on data from Jouzel et al. But the paleoclimate record also reveals that the current climatic warming is occurring much more rapidly than past warming events. As the Earth moved out of ice ages over the past million years, the global temperature rose a total of 4 to 7 degrees Celsius over about 5, years.
In the past century alone, the small paragraph on global warming has climbed 0. Temperature histories from paleoclimate data green line compared to the history based on modern instruments blue line suggest that global small paragraph on global warming is warmer now than it has been in the past 1, small paragraph on global warming, years, and possibly longer. Graph adapted from Mann et al. Models predict that Earth will warm between 2 and 6 degrees Celsius in the next century.
When global warming has happened at various times in the past two million years, it has taken the planet about 5, years to warm 5 degrees. The predicted rate of warming for the next century is at least 20 times faster. This rate of change is extremely unusual. Most often, global climate has changed because of variations in sunlight. Variations in the Sun itself have alternately increased and decreased the amount of solar energy reaching Earth.
Volcanic eruptions have generated particles that reflect sunlight, small paragraph on global warming, brightening the planet and cooling the climate. Volcanic activity has also, in the deep past, increased greenhouse gases over millions of years, contributing to episodes of global warming. We know this because scientists closely monitor the natural and human activities that influence climate with a fleet of satellites and surface instruments.
Remote meteorological stations left and orbiting satellites right help scientists monitor the causes and effects of global warming. On the ground, many agencies and nations support networks of weather and climate-monitoring stations that maintain temperature, rainfall, and snow depth records, and buoys that measure surface water and deep ocean temperatures.
Taken together, these measurements provide an ever-improving record of both natural events and human activity for the past years. Scientists integrate these measurements into climate models to recreate temperatures recorded over the past years. Climate model simulations that consider only natural solar variability and volcanic aerosols since —omitting observed small paragraph on global warming in greenhouse gases—are able to fit the observations of global temperatures only up until about After that point, the decadal trend in global surface warming cannot be explained without including the contribution of the greenhouse gases added by humans.
For example, two major volcanic eruptions, El Chichon in and Pinatubo inpumped sulfur dioxide gas high into the atmosphere. Temperatures across the globe dipped for two to three small paragraph on global warming. Natural influences on temperature—El Niño, solar variability, and volcanic aerosols—have varied approximately plus and minus 0.
Graphs adapted from Lean et al. Although small paragraph on global warming are active around the world, and continue to emit carbon dioxide as they did in the past, the amount of carbon dioxide they release is extremely small compared to human emissions. On average, volcanoes emit between and million tonnes of carbon dioxide per year.
By burning fossil fuels, people release in excess of times more, about 26 billion tonnes of carbon dioxide, into the atmosphere every year as of As a result, human activity overshadows any contribution volcanoes may have made to recent global warming.
Changes in the brightness of the Sun can influence the climate from decade to decade, but an increase in solar output falls short as an explanation for recent warming. The total energy the Sun radiates varies over an year cycle. During solar maxima, solar energy is approximately 0. The transparent halo known as the solar corona changes between solar maximum left and solar minimum right.
NASA Extreme Ultraviolet Telescope images from the SOHO Data Archive. Each cycle exhibits subtle differences in intensity and duration, small paragraph on global warming. As of earlythe solar brightness since has been slightly lower, not higher, than it was during the previous year minimum in solar activity, which occurred in the late s. Satellite measurements of daily light line and monthly average dark line total solar irradiance since have not detected a clear long-term trend.
NASA graph by Robert Simmon, based on data from the ACRIM Science Team. Scientists theorize that there may be a multi-decadal trend in solar output, though if one exists, it has not been observed as yet. Even if the Sun were getting brighter, small paragraph on global warming, however, the pattern of warming observed on Earth since does not match the type of warming the Sun alone would cause.
Satellite measurements show warming in the troposphere lower atmosphere, green line but cooling in the stratosphere upper atmosphere, small paragraph on global warming, red line.
This vertical pattern is consistent with global warming due to increasing greenhouse gases, but inconsistent with warming from natural causes.
Graph by Robert Simmon, based on data from Remote Sensing Systems, sponsored by the NOAA Climate and Global Change Program.
The stratosphere gets warmer during solar maxima because the ozone layer absorbs ultraviolet light; more ultraviolet light during solar maxima means warmer temperatures. Increased concentrations of carbon dioxide in the small paragraph on global warming and stratosphere together contribute to cooling in the stratosphere, small paragraph on global warming. To further explore the causes small paragraph on global warming effects of global warming and to predict future warming, scientists build climate models—computer simulations of the climate system.
Climate models are designed to simulate the responses and interactions of the oceans and atmosphere, and to account for changes to the land surface, both natural and human-induced. Though the models are complicated, rigorous tests with real-world data hone them into powerful tools that allow scientists to explore our understanding of climate in ways not otherwise small paragraph on global warming. Based on a range of plausible emission scenarios, average surface temperatures could rise between 2°C and 6°C by the end of the 21st century.
Model simulations by the Intergovernmental Panel on Climate Change estimate that Earth will warm between two and six degrees Celsius over the next century, depending on how fast carbon dioxide emissions grow. Scenarios that assume that people will burn more and more fossil fuel provide the estimates in the top end of the temperature range, while scenarios that assume that greenhouse gas emissions will grow slowly give lower temperature predictions.
The orange line provides an estimate of global temperatures if greenhouse gases stayed at year levels. Greenhouse gases are only part of the story when it comes to global warming. Changes to one part of the climate system can cause additional changes to the way the planet absorbs or reflects energy.
These secondary changes are called climate feedbacks, and they could more than double the amount of warming caused by carbon dioxide alone.
The primary feedbacks are due to snow and ice, water vapor, clouds, and the carbon cycle. Perhaps the most well known feedback comes from melting snow and ice in the Northern Hemisphere. Warming temperatures are already melting a growing percentage of Arctic sea ice, exposing dark ocean water during the perpetual sunlight of summer. Snow cover on land is also dwindling in many areas. In the absence of snow and ice, these areas go from having bright, sunlight-reflecting surfaces that cool the planet to having dark, sunlight-absorbing surfaces that bring more energy into the Earth system and cause more warming.
In the past years, the glacier has lost half its volume and has retreated more than 1. As glaciers retreat, sea ice disappears, and snow melts earlier in the spring, the Earth absorbs more sunlight than it would if the reflective snow and ice remained.
Photograph © Hugh Saxby. The largest feedback is water vapor. Water vapor is a strong greenhouse gas.
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2/1/ · Global warming and climate change refer to an increase in average global temperatures. Natural events and human activities are believed to be contributing to an increase in average global temperatures. This is caused primarily by increases in greenhouse gases such as Carbon Dioxide (CO 2) 6/24/ · June 24, by Prasanna. Paragraph On Global Warming: Global warming is the rise of average global temperature on the surface of the earth. It has been recognized as a severe threat to the environment since the s. The rate of increase in global temperatures sees accelerated growth for the last 5 decades Global warming is the phenomenon of a gradual increase in the temperature near the earth’s surface. This phenomenon has been observed over the past one or two centuries. This change has disturbed the climatic pattern of the earth
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