Explaining Climate Change

Climate change is not a new phenomenon. Earth's climate has always been in a state of evolution, so the fact that people are noticing changes is not surprising. The current global average temperature is approximately 60 degrees Fahrenheit; however, research into historic temperatures suggests that global average temperatures have ranged both higher and lower in the past. The warming trend that's occurring currently seems to be happening faster than it has happened in the past, which concerns scientists. The fear is that this natural variance is being impacted by human-induced warming and that this fast warming will have negative repercussions on the stability of Earth's climate in the long term.

What is the Greenhouse Effect?

The greenhouse effect describes the entrapment of some of the sun's energy near the Earth. Solar energy that radiates back into space after it touches Earth gets absorbed by greenhouse gases in the atmosphere. It is then re-emitted in every direction, and the energy that moves back down toward the Earth brings more heat with it.

Water vapor is the most important greenhouse gas, and it contributes to warming. However, water vapor only remains in the atmosphere for a few days. Carbon dioxide from the use of fossil fuels stays in the atmosphere for much longer periods. Natural reservoirs in the environment don't absorb carbon dioxide at the same rate as water vapor. Deforestation results in greater amounts of carbon dioxide in the atmosphere as well. Methane, nitrous oxide, and fluorinated gases also make up some of the greenhouse gases. Since the beginning of the industrial revolution, carbon dioxide and methane levels have gone up significantly.

Evidence that Supports Global Warming

Temperature data from the last 100 years indicates that the average temperatures of the Earth's surfaces have gone up about 1.4 degrees Fahrenheit. In addition, satellite data shows that the global sea level averages have gone up approximately three millimeters per year in the past few decades. Scientists theorize that this happens because of thermal expansion of seawater. As the seawater gets warmer, its molecules are packed less densely, which increases the overall volume of the oceans.

Melting mountain glaciers and a reduction of the polar ice sheets also have an impact on global warming. Not only are the glaciers in the Antarctic Peninsula getting smaller, glaciers located within the temperate regions are also retreating. Comparison of satellite records from 1979 highlight a major change from the sea ice present in the Arctic from then until now. The rate of decline is estimated to be 4 percent per decade, and in 2012 a new record was set for the minimum sea ice level. Additionally, the Greenland Ice Sheet has undergone record melting.

Satellites also showcase sea ice mass loss in the West Antarctic Ice Sheet. In East Antarctica, a recent study indicates that ice sheets are also beginning to lose mass. Loss of ice mass is not the only result of global warming, though. Sometimes warmer temperatures lead to more snows, which can increase ice mass. The changing climate also has an impact on land animals and vegetation. As plants flower and fruit earlier in the season, animals respond by shifting their range and territory to find food.

Future Temperature Predictions

The Intergovernmental Panel on Climate Change has a computer model that outlines potential scenarios for future temperatures. Most of these simulations expect a global surface temperature increase to exceed 1.5 degrees Celsius or about 35 degrees Fahrenheit by the end of the 21st century. If this shift comes to pass, the impact would have far-reaching implications for society.

Reducing greenhouse gas emissions dramatically would be helpful. However, the effects of the greenhouse gases will continue to be felt in the environment even if the emissions are cut. Large masses of ice and bodies of water don't respond to changes quickly. The greenhouse gases will also remain in the atmosphere for many decades.

Effects of Climate Change on Humans

Scientists aren't sure precisely about the effects of climate change on humans. However, it's possible that shortages of fresh water will occur, which will impact food production. Deaths will likely increase from storms, heat, floods, and droughts. Climate change is expected to have an impact on extreme weather, so some areas may have more rain than usual, while other areas have high temperatures and less rain. Sea levels are expected to rise as well. The poorest countries will be least able to respond to these climate changes.

Extinction of animal and plant species is anticipated as these species have trouble adapting to climate change, which will likely lead to malnutrition and other diseases. Oceans will become more acidic from carbon dioxide, which will affect coral reefs. Additional heating might also occur with the release of large quantities of methane when permafrost melts.

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