Climate Change Science
Scientists study Earth’s processes to improve understanding of global climate change. Topics include the greenhouse effect that keeps our planet from freezing, the gases that contribute to global warming, and the role of humans. They keep track of where temperatures are rising already, and how precipitation is changing around the world. One key area for study is how the changing climate may affect hurricanes.
The Greenhouse Effect and Global Warming
The greenhouse effect and global warming are related. The greenhouse effect refers to the process in which radiation emitted by the Earth is trapped by greenhouse gases in the atmosphere and returns to the Earth’s surface. This effect warms the surface and without it, temperatures on Earth would be near freezing. Human activity has amplified this process by increasing the greenhouse gases in the atmosphere, causing temperatures to rise. This is known as global warming.
If you’ve heard about climate change, then you’ve probably heard the term “greenhouse gas emissions”. But, do you know which gases these are? Do you know how they contribute to global climate change?
The three main greenhouse gases are carbon dioxide, methane, and nitrous oxide. The most important sources are burning fossil fuels (oil, coal, and gasoline) and changing forests to fields and settled areas.
Greenhouse gases change the amount of energy entering and exiting the Earth’s atmosphere. Before humans started burning fossil fuels, the energy from the sun that fell on Earth roughly equaled the energy that Earth radiated into space. Now the Earth absorbs more energy than it radiates. This leads to global warming.
How do we know that humans are involved in climate change?
People debate whether or not human activity is responsible for climate change. Climate does change through natural cycles and processes, such as variations in the orbit of the Earth. However, accumulating evidence strongly suggests that human activity is causing the climate to warm more than it would by natural processes alone.
To test this, scientists use global climate models to recreate the temperature trend of the past 150 years, which they then compare to the observed record. They make simulations with and without human activities included. The simulated temperature trend that most closely matches the observed data is the one with human activity included.
Global warming and the ozone hole
For a time, many people believed that the ozone hole was a primary cause of global warming. This is not the case. Damage to the ozone layer is unrelated to global climate change, aside from the fact that both are environmental problems caused by human activity.
It’s getting hot out here!
“The world is getting warmer” has become almost a refrain. It’s true that global average surface temperatures have risen over the past century. But while the Earth as a whole is hotter, where you live may not be getting warmer.
Although most areas of the globe are warmer than they were a century ago, different places have undergone this change at different rates and extents. Thus, the weather in your area could be colder than normal for a time. This doesn’t mean the global warming has stopped.
It’s raining! It’s drying out!
Trends in precipitation vary a lot from place to place. In the 20th century, regions such as eastern North and South America have had more rainfall, while others like southern Africa have experienced drying. The one precipitation trend that appears to be consistent across all areas is more extreme rainfall events. Rains are more likely to be heavy, when they do occur. When it rains, it pours!
Now that most scientists agree that humans are responsible for much of climate change, perhaps the question of most popular interest is whether or not climate change is causing more hurricanes. Many questions were raised after the active Atlantic hurricane season of 2005, which included Hurricanes Katrina and Rita.
Over the past 30 years, the trend has been towards longer and more intense hurricanes. This has been attributed to warmer sea surface temperatures from global warming. However, over the same time period, the frequency of the storms has not increased. Many factors affect the spawning of hurricanes, so scientists don’t yet know what role climate change will play in changing hurricane frequency.