This online module was developed by UNB Sustainability and the Office of Experiential Education to introduce the concept of climate change.

The difference between climate and weather is that weather can change quickly and suddenly. In contrast, climate describes the long-term pattern of weather in a particular area. For example, in general, there is hotter weather in Costa Rica compared to New Brunswick.

Climate change is defined as a long-term change in the average weather patterns that have come to define Earth's local, regional, and global climates.

But what does this mean?

• Hotter summers and more frequent heat waves
• Increases in forest fires
• Melting ice caps and glaciers
• Increases in severe weather such as hurricanes
• Changes in patterns of precipitation leading to droughts and flooding
• And more...

Many of these changes are already becoming visible and are taking heavy tolls on human health, infrastructure, food security, global biodiversity and where it is safe for humans to live.

In fact, many people argue that we are in the midst of a climate change crisis.

There are two types of actions being taken by world governments, industries, organizations, and communities in response to climate change. These are Adaptation (the process of making something suitable for a new use or purpose, such as developing new crops) and Mitigation (the act of reducing the severity, seriousness, or painfulness of something).

Much focus at the international level has been on mitigation. As our current crisis is the result of human activities that release greenhouse gases such as carbon dioxide and methane, limiting our production of these gases seems like a sensible goal. Strategies such as carbon taxes, emission caps, and carbon credits have all been suggested, but there are disagreements about how to implement these fairly and who should take more responsibility.

Most scientists agree that in order to avoid the worst of climate change, Earth’s global temperature cannot be allowed to increase by more than 1.5 - 2 degrees Celsius. To reach this target, global emissions must start declining by 2025 and half to a quarter of all emission cuts must occur by 2030. This means we’re on a very tight schedule.

In this module, we will take a look at the greenhouse effect, the main driver behind global climate change. We’ll look at how climate change integrates with the United Nations sustainable development goals and the role of the Intergovernmental Panel on Climate Change (IPCC). We’ll also consider some of the barriers slowing climate change action, as well as some of the more positive actions taking place.

Space is a cold place. So what makes Earth a place where life survives and thrives?

The short answer is the Greenhouse Effect.

Think of a greenhouse; the clear glass allows sunlight to pass through into the greenhouse while trapping the sun's heat inside; this keeps the plants warm at night and during the winter. This is similar to how the Greenhouse Effect keeps the Earth warm.

So, how does the Greenhouse Effect work?

The answer is our atmosphere - a thin layer of gases that surrounds the Earth. It allows energy produced by the sun, known as infrared radiation, to pass through and be absorbed by the Earth's surfaces like land and water; this causes the Earth's surface to warm. Without the gases that make up the atmosphere, infrared radiation would be reflected back into space.

Because this is so similar to how a greenhouse keeps plants warm, we call this the greenhouse effect.

The gases responsible for the greenhouse effect include carbon dioxide, methane, nitrous oxide, and water vapour. Certain levels of each of these gases naturally make up the atmosphere which also keep the Earth at a comfortable temperature. Cycles of nutrients have developed as part of Earth’s climate and ecosystems to keep things more or less in balance and make Earth a safe and comfortable place to live.

For example, carbon moves between the atmosphere as carbon dioxide and various carbon sinks, which store carbon and keep too much from building up in the atmosphere. Natural carbon sinks include forests, the ocean, and Earth’s soil.

But human activities release greenhouse gases and decrease the natural carbon sinks available. This is resulting in extra greenhouse gases, and while we need some to keep Earth habitable, too much of the greenhouse gases can overheat the Earth.

In fact, humans are now responsible for over 1.5 trillion tons of carbon dioxide in our atmosphere that wouldn’t have been there otherwise. And our activities continue. In 2019 alone, we released 37 billion tons more.

The breakdown of global greenhouse gas emissions looks roughly like this (pie chart):

With electricity and heating responsible for about ¼ of all emissions, agriculture, and land use (including deforestation) responsible for another ¼, industry (such as manufacturing) responsible for about 20%, transportation for 14%, and buildings responsible for about 6.4%. The remaining 9.6% comes mostly from the extracting, processing, and shipping of fossil fuels.

In terms of countries, about half of all greenhouse gases that have been released since the Industrial Revolution in the 1800s, have been released by North America and Europe. Today, on an annual basis, China, the United States, the EU, and India are the greatest contributors. Canada is ranked 10th in world for total emissions but actually has the highest greenhouse gas emissions per capital.

One of the tricky things to remember about greenhouse gases, is that they can stay in the atmosphere for a very long time. Nitrous oxide can stay in the atmosphere for up to 114 years before it is broken down, while carbon dioxide can stay in the atmosphere for between 300 to 1000 years before it settles back down into a carbon sink. This means that the carbon dioxide we release today could still be affecting Earth’s climate in the year 3000.

It can be difficult to think about something today having such long-lasting effects, and many of the ways Western societies make decisions don’t take quite such a long-term view.

We can look to Indigenous cultures, however, for guidance on this type of long-term thinking. The Haudenosaunee Confederacy teaches the Seventh Generation Principle, which suggests that decisions made today should result in a sustainable world for seven generations to come.

Coping with climate change and its effects, and guarding against worse ones in the future, will require cooperation between nations, industries, and individuals to limit and control greenhouse gas emissions.