Global Warming is a process of increasing the average temperature of the atmosphere,ocean, and Earth's land.
Why global warming could happen ?
global warming caused by greenhouse effect. "Greenhouse effect" is the warming that occurs when certain gases trap heat in Earth's atmosphere. These gases allow light but keep heat from escaping, like the glass walls of a greenhouse.
First, sunlight shines into the Earth's surface, where it is absorbed and then radiated back into the atmosphere as heat. In the atmosphere, "greenhouse" gases trap some of this heat, and the rest escapes into space. More greenhouse gases in the atmosphere, the more heat trapped.
Scientists have known about the greenhouse effect since 1824, when Joseph Fourier was calculated that the earth will be much cooler if there were no atmosphere. This greenhouse effect is what makes the Earth's climate livable. without it,
the earth's surface would be on average about 60 degrees Fahrenheit colder. In 1895, Swedish chemist Svante Arrhenius discovered that humans could enhance the greenhouse effect by making carbon dioxide, a greenhouse gas. He kicked off 100 years of climate research that has given us a sophisticated understanding of global warming.
Level of greenhouse gas (GHG) emissions have gone up and down during the history of the earth, but they have been fairly constant for several thousand years. Global average temperature has stayed fairly constant during that time also, until now. Through the burning of fossil fuels and other greenhouse gas emissions, humans are increasing the greenhouse effect and global warming.
Scientists often use "climate change" instead of the term global warming.
This is because as the earth's average temperature rose, the winds and ocean currents move heat around the world in ways that can cool some areas, warm others, and changes in the amount of rain and snow fall. As a result, the climate changes differently in different areas.
what should we do to slow global warming?
The evidence that humans are causing global warming is strong, but the question of what to do about it remains controversial. Economics, sociology, and politics are all important factors in planning for the future.
Even if we stopped emitting greenhouse gases (GHGs) today, the Earth would still warm by another degree Fahrenheit or so. But what we do from today forward makes a big difference. Depending on our choices, scientists predict that the Earth could eventually warm by as little as 2.5 degrees or as much as 10 degrees Fahrenheit.
A commonly cited goal is to stabilize GHG concentrations around 450-550 parts per million (ppm), or about twice pre-industrial levels. This is the point at which many believe the most damaging impacts of climate change can be avoided. Current concentrations are about 380 ppm, which means there isn't much time to lose. According to the IPCC, we'd have to reduce GHG emissions by 50% to 80% of what they're on track to be in the next century to reach this level.
Is this possible?
Many people and governments are already working hard to cut greenhouse gases, and everyone can help.
Researchers Stephen Pacala and Robert Socolow at Princeton University have suggested one approach that they call "stabilization wedges." This means reducing GHG emissions from a variety of sources with technologies available in the next few decades, rather than relying on an enormous change in a single area. They suggest 7 wedges that could each reduce emissions, and all of them together could hold emissions at approximately current levels for the next 50 years, putting us on a potential path to stabilize around 500 ppm.
There are many possible wedges, including improvements to energy efficiency and vehicle fuel economy (so less energy has to be produced), and increases in wind and solar power, hydrogen produced from renewable sources, biofuels (produced from crops), natural gas, and nuclear power. There is also the potential to capture the carbon dioxide emitted from fossil fuels and store it underground—a process called "carbon sequestration."
In addition to reducing the gases we emit to the atmosphere, we can also increase the amount of gases we take out of the atmosphere. Plants and trees absorb CO2 as they grow, "sequestering" carbon naturally. Increasing forestlands and making changes to the way we farm could increase the amount of carbon we're storing.
Some of these technologies have drawbacks, and different communities will make different decisions about how to power their lives, but the good news is that there are a variety of options to put us on a path toward a stable climate.
