The effects of Climate Change
People are causing global warming by burning fossil fuels (like oil, coal and natural gas) and cutting down forests. Scientists have shown that these activities are pumping far more CO2 into the atmosphere than was ever released in hundreds of thousands of years. This build up of CO2 is the biggest cause of global warming.
We know that the planet has been warming over the past several decades and Arctic ice has been melting persistently. And unlike the earlier periods of Arctic warmth, there is no expectation that the current upward trend in Arctic temperatures will reverse, the rising concentrations of greenhouse gases will prevent that from happening.
- Ice is melting worldwide, especially at the Earth’s poles. This includes mountain glaciers, ice sheets covering West Antarctica and Greenland, and Arctic sea ice.
- Sea level rise became faster over the last century.
- Some butterflies, foxes, and alpine plants have moved farther north or to higher, cooler areas.
- Precipitation (rain and snowfall) has increased across the globe, on average.
- Other effects could happen later this century, if warming continues.
- Hurricanes and other storms are likely to become stronger.
- Species that depend on one another may become out of sync. For example, plants could bloom earlier than their pollinating insects become active.
- Floods and droughts will become more common. Rainfall in Ethiopia, where droughts are already common, could decline by 10 percent over the next 50 years.
- Less fresh water will be available. If the Quelccaya ice cap in Peru continues to melt at its current rate, it will be gone by 2100, leaving thousands of people who rely on it for drinking water and electricity without a source of either.
- Some diseases will spread, such as malaria carried by mosquitoes.
- Ecosystems will change—some species will move farther north or become more successful; others won’t be able to move and could become extinct. Wildlife research scientist Martyn Obbard has found that since the mid-1980s, with less ice on which to live and fish for food, polar bears have gotten considerably skinnier. Polar bear biologist Ian Stirling has found a similar pattern in Hudson Bay. He fears that if sea ice disappears, the polar bears will as well.
Source for climate information: IPCC, 2007