The term Climate Change refers to any change in climate over time, whether as a result of natural phenomena or human activity.

Natural fluctuations in our climate typically occur over long periods of time. What is not natural is the accelerated rate of change that is happening today as a result of significant increases in carbon dioxide (CO₂) and other greenhouse gases (GHGs) in our atmosphere. GHGs are a natural part of the atmosphere and move through a process called the carbon cycle. GHGs in the atmosphere are absorbed through natural processes (like plant photosynthesis) and are temporarily stored. These materials and processes eventually release this carbon back into the atmosphere as GHGs and the process starts anew. The planets atmosphere and the oceans and forests are in balance with no “new” GHGs entering the system. The only way for GHG concentrations to increase is through events such as volcanic eruptions or human activities. The source of the build-up of new GHGs in the atmosphere happening today can be traced to human activity. Since the Industrial Revolution, we have relied on fossil fuels to power our lives. GHGs are released when we burn fossil fuels to power our vehicles, heat or cool buildings, or conduct a variety of other industrial activities. The carbon in fossil fuels is trapped in the ground and is only released to the atmosphere through human activity.

Since industrialization, the human hand in increasing atmospheric GHG concentrations has become evident. Current global warming trends and resulting climate change cannot be explained by natural forcing alone. Anthropogenic (human) sources of GHGs need to be factored in if we are to fully explain the trends that we are currently observing.

When climate change occurs this suddenly, it can have a significant impact on people, economies and the environment. Only by slowing and ultimately reversing the build-up of GHGs in the atmosphere can we hope to mitigate the effects of global climate change.

Adapted from the Government of Manitoba STEM Site

Climate and Weather

People may ask, “how can we predict climate change over decades when we can’t get the weather right for tomorrow?” This question goes to the hart of the difference between weather and climate. Weather is the condition of the atmosphere over a short period of time, and climate is how the atmosphere "behaves" over relatively long periods of time. In some ways climate is easier to predict than weather. For example, you may not be able to predict the weather for next weekend, but you would be confident in the fact that in Manitoba it is going to be colder in February than in August. Manitoba has a climate that is relatively steady year on year, whereas the weather can change over the course of a day from sunny to stormy.

When we talk about climate change, we talk about changes in long-term averages of daily weather. It may be hotter or colder than expected on any given day, but if summers seem hotter lately than they were a decade ago, then the recent climate may have changed. In Manitoba, some farmers have even noticed that spring thaw comes earlier now than it did 30 years ago. An earlier springtime is indicative of a possible change in the climate.

In addition to long-term climate change, there are shorter term climate variations. This so-called climate variability can be represented by periodic or intermittent changes related to El Niño, La Niña, volcanic eruptions, or other changes in the Earth system.

Adapted from the NASA climate website