U.S. politicians are finally admitting that we're in the midst of global warming, but they don't all agree that this is caused by human activity. While it's vital to plan for the future now?no matter how we got into this situation?it's important to know how much influence human activity has had on climate change, because that's where we can make the biggest changes.
Climatologist Peter Stott used computer modeling to look at temperatures in North America between 1900 and 1999 in order to see if man did?or did not?have an influence on them. His team created several virtual 20th century North Americas, with seas, trees, mountains, volcanoes, clouds and weather systems. They introduced volcanic action and solar activity to some, both of which can cause natural climate change. They ran each model with?and without?the added greenhouse gases from human activities, such as power plants and car exhausts. If one of the models turned out to match what has really happened over the last 100 years, then this would show what caused it.
So do humans influence global warming? Yes?and no. In the first half of the century, the climate change matched the "natural influence" model. However, in the second half of the century, from 1950 to 1999, the climate change of North America closely matched the "human influence" model. This means we didn't begin to change the weather until we reached a certain level of greenhouse gas emissions, so if we can reduce those emissions, we can return to an era when global warming is due only to non-human activities. We may still have to plan, but we'll no longer feel guilty, and we'll at least have done what we can to slow it down.
If you want to get a reading from a medium but don't want be fooled by a fake, you need to learn some of secrets that are on this week's Dreamland.
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