Q&A
What is Global Warming?
Global Warming is the slow increase in the average temperature of the earth's atmosphere because an increased amount of the energy (heat) striking the earth from the sun is being trapped in the atmosphere and not radiated out into space.
The earth’s atmosphere has always acted like a greenhouse to capture the sun’s heat, ensuring that the earth has enjoyed temperatures that permitted the emergence of life forms as we know them, including humans.
Without our atmospheric greenhouse the earth would be very cold. Global warming, however, is the equivalent of a greenhouse with high efficiency reflective glass installed the wrong way around.
Ionically, the best evidence of this may come from a terrible cooling event that took place some 1,500 years ago. Two massive volcanic eruptions, one year after another placed so much black dust into the upper atmosphere that little sunlight could penetrate. Temperatures plummeted. Crops failed. People died of starvation and the Black Death started its march. As the dust slowly fell to earth, the sun was again able to warn the world and life returned to normal.
Today, we have the opposite problem. Today, the problem is not that too little sun warmth is reaching the earth, but that too much is being trapped in our atmosphere.
So much heat is being kept inside greenhouse earth that the temperature of the earth is going up faster than at any previous time in history. NASA provides an excellent course module on the science of global warming.
How does global warming drive Climate Change?
Heat is energy and when you add energy to any system changes occur.
Because all systems in the global climate system are connected, adding heat energy causes the global climate as a whole to change.
Much of the world is covered with ocean which heats up. When the ocean heats up, more water evaporates into clouds.
Where storms like hurricanes and typhoons are forming, the result is more energy-intensive storms. A warmer atmosphere makes glaciers and mountain snow packs, the Polar ice cap, and the great ice shield jutting off of Antarctica melt raising sea levels.
Changes in temperature change the great patterns of wind that bring the monsoons in Asia and rain and snow around the world, making drought and unpredictable weather more common.
This is why scientists have stopped focusing just on global warming and now focus on the larger topic of climate change.
5 Causes of Global Warming:
Cause #1: Variations in the Sun's Intensity
The Earth receives its warmth from the sun, so it's reasonable to suspect that our home star may be one of the reasons for global warming. Although the amount of energy coming from the sun does vary and may have been responsible for warming in the past, however, NASA and the Intergovernmental Panel on Climate Change (IPCC) have ruled this out as a cause of the current warming trend. The average energy coming from the sun generally has remained constant since 1750, and the warming does not occur uniformly throughout the atmosphere. The upper layer is actually cooling as the bottom layer becomes warmer.
Cause #2: Industrial Activity
Since the Industrial Revolution, humans have been burning fossil fuels such as coal and petroleum for energy, which releases carbon dioxide into the atmosphere. A quarter of this is for heat and electricity, while another quarter is for other industrial processes and transportation, which includes gasoline- or diesel-powered cars, trucks, trains and airplanes. The other half of the energy is used for various other purposes, including agriculture, cement production and oil and gas production. These processes also release other greenhouse gases, such as methane and CFCs, although the concentration of CFCs has declined since their use was banned in 1988.
Cause #3: Agricultural Activity
The agricultural practices that produce food for the people on earth is another of the human causes of climate change. The use of both commercial and organic fertilizers releases nitrous oxide, a powerful greenhouse gas. Methane, another important greenhouse gas, comes from many natural sources, but also from the digestive systems of livestock raised for meat production as well as the decomposition of waste in landfills and the burning of biomass.
Cause #4: Deforestation
The increased demand for meat and dairy cattle has lead to the creation of feed lots in otherwise forested areas. Logging for wood and paper and clearing for crop production also requires trees to be cut, sometimes illegally. One mature tree absorbs as much as 48 pounds of carbon dioxide each year, and by one estimate, 3.5 to 7 billion are cut every year. According to Scientific American, deforestation is responsible for 15 percent of the greenhouse gases in the atmosphere.
Cause #5: Earth's Own Feedback Loop
As the atmosphere warms, it is able to hold more water, which is already the most abundant greenhouse gas. This creates a feedback loop that accelerates global warming. It also creates more clouds, rainstorms and other symptoms of climate change. At the poles, the warming of the atmosphere melts the ice cover, exposing water, which is less reflective than ice. The water absorbs the sun's heat, and the oceans also become warmer as a result.