Our atmosphere is being filled by significant quantities of human-caused greenhouse gases. When this happens, a lot of the infrared radiation that would otherwise escape gets trapped. As a result, the temperature of the Earth's atmosphere and oceans gradually gets warmer.
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The atmosphere.
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Greenhouse gases are gases in our atmosphere that hold heat.
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Carbon dioxide (CO₂)
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When the sun's energy enters the atmosphere, some of that energy warms up the Earth and atmosphere. Then the energy is re-radiated back into space in the form of infrared radiation. The greenhouse gases soak some of the infrared radiation, preventing it from escaping into space. In a pre-industrial world, just the right amount of the sun's energy was soaked up by the greenhouse gases. This created a greenhouse effect, a wonderfully balanced system that kept the Earth from becoming too hot like Venus or too cold like Mars.
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When too much of the atmosphere is made up of greenhouse gases, it leads to global warming. The problem we now face is that the atmosphere is being filled by significant quantities of human-caused carbon dioxide and other greenhouse gases. This traps a lot of the infrared radiation that would otherwise escape. As a result, the temperature of the Earth's atmosphere and oceans is getting dangerously warmer. This is what the climate crisis is all about.
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Yes, here's evidence that global warming is already happening:

• The melting and disappearance of snow and glaciers.
• While some warming is normal, the increases in temperature during the past 50 years have been above the norm. Not only have the temperatures been the highest ever recorded, but studies have shown that the warming is accelerated and temperatures will continue to increase.
• There are more frequent hurricanes. There are also hurricanes occurring in places where they have never occurred before.
• Permafrost is thawing.
• The Antarctic Peninsula Ice Shelf is melting.

Glaciers provide drinking water. If they disappear, the human race will face a very serious drinking water shortage.
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Yes! We know this from the studies of glacial ice. Glacial ice is deposited in layers, so there is a new top layer every year. By taking out long cylinders of ice from glaciers around the world, scientists can measure many things, including the average world temperature each year. They can read the ice like a forester "reads" tree rings.
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Scientists can also measure carbon dioxide that was in the Earth's atmosphere in these glacial ice samples. These show that there was more carbon dioxide in the atmosphere in the years that were the warmest.
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One way humans have contributed to global warming is through the increased world population. We have quadrupled world population in less than a hundred years. Our impact on the earth is greater now.
Technology has also contributed to global warming. Irrigation has diverted too much water from natural sources. Strip mining has ravaged the land. Cars add a significant amount of carbon dioxide to the atmosphere.
These are just a few ways we have contributed to global warming. There are a lot more ways we have caused damage to the Earth and atmosphere.
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The United States.
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Yes! As global awareness has grown, new technology has developed that can help fight global warming. Some examples are:

• Solar Panels
• Geothermal Power Stations
• Fluorescent Lightbulbs
• Green Roofs
• Hybrid Cars
• Hydrogen Fuel-Cell Buses
• Wind Power

The Kyoto Protocol is a treaty that sets targets for limiting greenhouse gases.
Only two advanced nations haven't ratified the Kyoto Protocol. Which two nations haven't ratified the Kyoto Protocol?
Australia and the United States.
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