What is Climate Change?

What is Climate Change. (PDF 219KB)

The Earth’s climate has always changed. The flux between ice ages and inter-glacial periods follows a pattern. The difference now is that human activities are influencing the climate. The burning of fossil fuels releases greenhouse gases into the atmosphere, and these gases trap heat near the Earth.

Levels of carbon dioxide, the most significant of greenhouse gases, are at 381 parts per billion in the atmosphere and rising. Looking at ice core samples dating back 400,000 years, the level of carbon dioxide is higher now than it has ever been.

The following graph shows how temperature and carbon dioxide levels move together.

Over the last 50 years, the global average temperature has risen 1°C. In the area spanning from Alaska to Yukon, the average temperature has risen 3°C. Although a few degrees may seem like nothing to worry about, an ice age requires only 8°C in temperature shift.

The North is on the front-line of climate change. It is warming more rapidly than the South due to melting ice. When snow and ice melt, more sunlight is absorbed by the darker, exposed earth, causing temperatures to rise and snow and ice to melt more quickly. Although trends show this happening across the North, the two regions that have seen the greatest increase in temperature are Yukon and Siberia.