Climate change and America's military
Comment: 12 days ago
When do you think the planet would have recovered from this ice age if humans were not on the planet? You didn't watch that video did you? The answer is there, but I'll summarise.
Right now we are in a warm period of the Quaternary ice age that began about 2.5 million years ago, heading towards the next glaciation (cold period) within the Quaternary period. If humans did not exist, the climate would be cooling, reaching the the coldest period in 25,000 to 50,000 years before it warms up again. These cycles are caused by a combination of factors that include the Earth's orbit around the sun, the Earth's tilt and wobble, and Jupiter's and Saturn's orbits.
Also, we don't "recover" from ice ages. Ice ages last much longer than warm periods.
What year will it be now that humans are on the planet when all the ice is gone? That depends on what humans do. If we keep adding billions of tons of greenhouse gases to the atmosphere every year, then probably not very long. On geological time scales, pretty much instantly.
If you look at the whole picture, it's easy to see why humans are responsible for the warming today. 2 factors dictate the climate, the heat from the sun and the composition of the atmosphere. The ice age cycles are caused by the movement of planets, so only affect the heat from the sun. Because orbit changes cycle over tens of thousands of years, even hundreds of thousands, they cannot account for the rapid temperature change we have had - 1C in 100 years.
The sun also has its own cycles. There's an 11 year cycle for something, can't remember exactly what. And there are other cycles as well. In the 20th century, the sun's output did rise, and so did the temperature of the climate. But since the 1970s, the sun's output has been reducing yet the temperature has continued to rise. So global warming today is not caused by more heat coming from the sun, because less heat is actually coming from the sun.
The other factor that affects the climate is the composition of the atmosphere. Many things can affect the atmosphere, like an asteroid strike, over active volcanos; global algae bloom, nuclear war etc. The atmosphere has dramatically changed in the last 100 years, or at least the greenhouse gases in the atmosphere. CO2 has increased by over 40%. Methane by 250%. Both are powerful greenhouse gases, meaning they trap heat.
So there you have it, It's those pesky greenhouse gases that done it.