Climate change is different from the changes in weather you see from day to day. It’s the kind of change in weather patterns your parents or elders may have noticed. You may have heard them say that winters are not as cold as they used to be, or that the ice is thinner on the lakes and in the Arctic. Scientists agree with them. The climate is changing. And it is changing more quickly in the north than anywhere else.

Up until the last hundred years or so, the earth’s climate stayed much the same—for almost 10,000 years. Sure, there were some weird winters and really hot summers, and some cold stretches, but temperatures averaged out over the years, and you knew what to expect season to season. Little changed until about a century ago when the average temperature of the globe started to rise.

Over the last century, average temperatures in many Arctic regions climbed by as much as 5°C. The average worldwide temperature increased about 0.6°C.

Some scientists predict that, if these changes continue over the next 100 years, temperatures in the Arctic could rise by as much as twice the global average—and that’s expected to go up by 1.4° to 5.8°C.

That doesn’t sound like a problem, does it? Don’t people in the North deserve a break from long, cold winters? Maybe, but climate change means a lot more than warmer temperatures. It may change many of the things we value about the north: our environment and plants and animals. That makes climate change something worth checking out.

Greenhouse Gases: The Earth’s Blanket

To understand climate change, you have to know something about our atmosphere. Even though we can see through it, as far as the earth is concerned, the atmosphere works like a blanket. It’s made up of the air we breathe, plus small amounts of greenhouse gases (GHGs) that can trap heat like a warm, fleecy blanket. If you are chilly at night and cover up with a blanket, the warmth given off by your body gets trapped in it and keeps you cozy. GHGs in the atmosphere do the same thing for the Earth. They trap some of the heat that the earth absorbs from the sun. This trapping of warmth is known as the “greenhouse effect.”

If the earth’s atmosphere didn’t have some greenhouse gases, heat would be lost to space and we’d have temperatures more like those on Mars. There, they go up to 37°C during the day–bathing suit weather–but down to, more than minus 100°C at night–tough to survive. The greenhouse gases in our atmosphere help make life on earth possible.

Too Many GHGs—Too Many Blankets

The amount of greenhouse gases we had in the atmosphere for about 10,000 years helped to keep the climate pretty much the same over that period of time. The earth’s environment, plants and animals (including us) adapted to that climate. A change in the amount of greenhouse gases could mean too much heat—or too little. That could affect us, and other life on the planet, by changing our environment.

Greenhouse gases need to be kept in a delicate balance. And more greenhouse gases could be too much of a good thing.

Why are we warming up?

Right now, human activities are tipping the balance of gases in the atmosphere. They are changing our climate. We are adding too many heat-trapping greenhouse gases to the atmosphere. The result is some very weird weather—more heat, more storms, more rain in some places and seasons, and more drought and unusual temperatures in others. This buildup of GHGs and what it does to our climate is sometimes called the Enhanced Greenhouse Effect.

So, what’s a few degrees?

A few degrees up or down don’t make a big difference day-to-day or even year-to-year. But over many years, it can be a big deal. During the last Ice Age, the earth’s average temperature was only 4° to 6°C cooler than it was for the last 10,000 years–that stable climate period we’ve talked about. During that Ice Age, a thick sheet of ice covered nearly all of Canada, and many plants and animals disappeared completely. So a few degrees can make a big difference over the long haul.

Where Are all these GHGs Coming From?

About 200 hundred years ago, humans began to develop faster ways of making and moving things. This period of time was known as the Industrial Revolution. The energy that made the revolution possible came from fossil fuels. These are fuels such as coal, and the diesel oil, furnace oil, kerosene and gasoline that come from petroleum.

When we use fossil fuels to run our cars, trucks, boats, airplanes and snowmobiles, we release greenhouse gases. We may also release GHGs when we heat our homes, run our industries or generate electricity.

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