Please forward this error screen to 209. Terrorist attacks cause worldwide panic and horror, but their effects are usually global investing made simple localized.
Global warming, which is a gradual rising of Earth’s temperature, is different from all these, representing a scale of threat greater than anything humans have faced in recent history. Photo: Is global warming too hot an issue for politicians to handle? This falsely colored image shows the amount of heat leaving different parts of Earth, as measured by NASA’s Terra spacecraft. The blue areas are coldest, where thick clouds prevent heat from escaping. In the yellow areas, there is little cloud cover so the heat escaping is at a maximum. Imagine you live in a timber shack in Alaska.
It’s chilly up there, so you build yourself a huge log fire and pile on all the wood you can find. To start with, the fire seems a great idea—especially since it’s so cold outside. The shack warms up slowly, but predictably, and it’s soon pretty cosy. Since the shack is much warmer than the atmosphere and ground that surround it, it loses heat quite quickly. A NASA map of global sea surface temperatures produced using infrared measurements taken by a satellite in space. Red and yellow areas are hottest, green and blue are coldest.
Picture courtesy of NASA on the Commons. Global warming is working a bit like this. Thanks to a variety of things that people do, Earth is getting slightly warmer year by year. It’s not really warming up noticeably—at least not in the short term. In fact, since 1900, the whole planet has warmed up only by around 0. Gases high in the atmosphere, such as carbon dioxide and methane, behave like a giant piece of curved glass wrapped right round the planet. When the Sun’s radiation enters our atmosphere, it heats our planet.
Like all hot objects, Earth gives off some of its heat as radiation of its own. Some of this radiation passes straight through the atmosphere and disappears off into space. However, some is reflected back again by the “blanket” of greenhouse gases in the atmosphere. The more greenhouse gases there are, the more heat is trapped and the hotter Earth becomes. Photo: Warming Island: These photos taken from the USGS Landsat satellite in 1985, 2002, and 2005 show how a new island has appeared in Greenland following the melting of an arctic glacier.
Melting glaciers are one indication that the world is warming up. Thanks to all the fossil fuels we burn, there is now more carbon dioxide in the atmosphere than at any time in the last 420,000 years. However, the actual amount of carbon dioxide in the atmosphere is still relatively small. Most people have no idea how much carbon dioxide they generate each day.
The Carbon for kids web page gives you some idea what your personal carbon dioxide emissions look like. The United States produces roughly 20 tonnes of carbon dioxide for each one of its citizens each year. The problem is getting worse all the time. Currently, 80 percent of our energy comes from fossil fuels. And the amount of energy people use is increasing too, not least because developing countries such as China and India are becoming more affluent. Chart: Who emits most carbon dioxide? Climate is the pattern of weather in a particular place: how much sunlight and rainfall it gets, how windy it is, and so on.
The world’s weather is entirely powered by the Sun. Since Earth rotates on a tilted axis, different parts of our planet are heated by different amounts at different times of year, making some regions hotter than others and causing the seasons. Scientists believe that greater amounts of carbon dioxide in the atmosphere, and hotter temperatures on Earth, will significantly change the climate across the whole planet. This climate change is already beginning to happen in parts of the world. If you live in a chilly place like Alaska or Greenland, you might think a bit of global warming sounds like a great idea. But climate change doesn’t necessarily mean things will get hotter. Photo: Will global warming bring more hurricanes?
Earth’s climate has been changing regularly for hundreds of millions of years, sometimes getting colder and sometimes warmer. Everyone knows about Ice Ages—those periods of history when Earth was far colder than it is now. The climate change people talk about today seems to be different. IPCC Climate Change 2014, Synthesis Report, p.