You’ve probably heard people talking about climate change – at school, on the news, at home. But what is it and why is it so important?
What is Climate?
Climate is often confused with weather, and although they are similar they are different things. When we refer to weather we mean what’s happening in a relatively small area, like a city or part of the country, over a few days. Climate is the bigger picture – things like rainfall, temperature and so on, but over an entire country or region and over a much longer period of time. For example, in the UK where I live we can have hot dry weather in the summer and snow in the winter, but the climate is temperate, meaning that it’s usually somewhere in between.
How is Our Climate Changing?
The Earth’s climate is getting warmer. In fact it has warmed up faster in the last 50 years than in the 50 years before that, which means that the rate of warming is getting faster.
Hasn’t Earth Always had Warmer and Cooler Periods?
It’s true that throughout its life the Earth has had different climates, including ice ages. We know this because scientists are able to study very deep layers of ice in the Arctic, testing the air bubbles trapped within, to see how much carbon dioxide (CO2) they contain. More CO2 means that the atmosphere was warmer and so the Earth was too. Other scientists do the same sort of testing on deep layers of mud and sediment below lakes.
However, when the Earth has warmed up in the past it was usually very slowly, with the temperature increasing by between 4 and 7 degrees Celsius over a period of roughly 5,000 years. In the last century alone the Earth’s climate has increased in temperature by 0.7 degrees Celsius; that’s ten times faster than in the past, and the rate of warming seems to be increasing.
Why is This Happening?
The more carbon dioxide there is in the atmosphere, the warmer the Earth becomes. This is because CO2 is a greenhouse gas, which means that it helps trap warm air between the planet’s surface and the outer atmosphere. If greenhouse gases didn’t exist the Earth would be frozen solid! Too much CO2 in the atmosphere means that too much warm air is trapped, which causes the planet’s temperature to increase.
Humans are burning ever more fossil fuels like oil, gas and coal, in order to power our cars and factories, heat our houses, and to create electricity. The rate of fossil fuel use has increased from zero, to occasional (medieval times) to excessive. This means that the amount of CO2 released has also drastically increased.
More CO2 in the atmosphere means warmer temperatures, and when the temperature goes up so does the CO2 in the atmosphere!
There are some people who don’t believe that human activity is causing climate change, or even that it’s happening at all. However, 97% of climatologists (scientists who study the climate) are convinced that human activity is a large part of the causes of global warming.
Why is Climate Change a Problem?
When the Earth warms up, so do the oceans. This means the ice in the Arctic and Antarctic begins to melt, causing water levels to rise. As the oceans warm up their water expands, taking up more space. Globally the sea levels have risen by almost 17cm over the last century; in the last 10 years they’ve risen twice as fast. Every 2.5cm increase in sea levels means that between 1 – 2.5 metres of beach disappears under the water.
The warmer temperatures can have a devastating effect on plants and animals, and have a knock on effect on us humans! Hibernating animals can’t hibernate long enough, so they have to spend more time and energy looking for food, which is scarce during winter. Animals accustomed to living in icy landscapes are losing their homes. Trees and plants aren’t getting as much water because rising temperatures cause droughts; if the plants and forests die, the animals (and humans!) will suffer. Plants absorb CO2 and release oxygen so if they die even more CO2 will end up in the atmosphere.
How Can I Help?
There are lots of things we can do to use less energy, and help slow global warming and climate change. Here are some suggestions, but I bet you can think of more!
Turn down your thermostat, and wear extra layers instead of turning on the heating. Healthier for both you and the planet!
Artists from around the world have painted canvases illustrating the human impact of climate change in their countries. Sixteen of these canvases were exhibited at the UN Climate Negotiations in Poznan, Poland in 2008.
Artist: Ashley Cecil
Louisville, Kentucky, USA
“It’s hard to feed a family when you can’t farm. For people in rural areas, farming is often their only means of survival. But farming is hard these days because of changing temperatures. I wanted to show that the women have no crops to harvest – just dust and an empty bowl.”
Sam blogs about all kinds of science at www.samanthagouldson.com.