Climate ChangeENVIRONMENTAL ISSUES

The ultimate concern is that if runaway global warming occurred, temperatures could spiral out of control and make our planet uninhabitable.... this is the first time that a species has been at risk of generating its own demise.… The dinosaurs dominated the earth for 160 million years. We are in danger of putting our future at risk after a mere quarter of a million years. Michael Meacher, UK Minister for the Environment 1997-2003, The

Guardian, 14 February 2003

Climate change is a global challenge that demands a global response. Yet there are nations that resist, voices that attempt to diminish the urgency or dismiss the science, or declare, either in word or indifference, that this is not our problem to solve. Well, let me tell you, it is our problem to solve... To the reticent nations, including the United States, I say this: There is such a thing as a global conscience.

Canadian Prime Minister Paul Martin, quoted in the L.A. Times

Climate is an average of weather over a long period of time in a given place. The Earth's natural climate is constantly changing, and in the first few hundred million years of Earth's formation, temperatures far exceeded what they are now. Dramatic changes from the tropical conditions of the Earth associated with the existence of dinosaurs to the ice ages have been natural throughout Earth's history.

The following graph shows the variation of global mean temperatures from 1880 to 2006 relative to the mean temperature during the base period from 1951 to 1980. What trend does the chart illustrate? Would the magnitude of the trend increase or decrease if annual mean temperature was plotted against a base period from 1881 to 1910? Consider how the base period that is selected impacts on the visual presentation of the data.

The Greenhouse Effect

Did you ever get into a car after it sat in the Sun with the windows closed? Even if the Sun is out on a cool day, the car will heat up. This is because of the greenhouse effect. The greenhouse effect is a heat-trapping process that occurs naturally in the atmosphere. Incoming energy from the Sun penetrates the atmosphere to warm the Earth. The planet then radiates heat back out toward space. Some of the outgoing heat is absorbed by greenhouse gases in the atmosphere and re-emitted back to the Earth.

Greenhouse gases (GHGs) are gases in the atmosphere that increase the greenhouse effect (capable of absorbing the infrared radiation emitted by the Earth). Some of the GHGs are human-made from the combustion of fossil fuels for cars or from producing heat and electricity and some are naturally produced in the environment.

The Greenhouse Gases:

Carbon Dioxide (CO2) is produced by the combustion of fuel, deforestation, and industrial processes. It is also produced naturally in the environment through the decay of organic matter and respiration by living things.

Methane (CH4) is produced in livestock and rice cultivation, in biomass burning, and in the decomposition of landfills. Methane release also occurs naturally in wetland areas. Methane exerts 21 times the greenhouse effect of CO2.

Nitrous oxides (N2O) are produced in the burning of fossil fuels, wood combustion, and the production of nitrogenous fertilizers; anaerobic bacteria in the soil also naturally produce it. Nitrous oxides exert 310 times the greenhouse effect of CO2.

Hydrofluorocarbons (HFCs) are found in sources including foam insulation, metal production, and coolants in refrigerators and air conditioners; they are not produced in nature. HFCs exert 140 to 11 700 times the greenhouse effect of CO2.

Perfluorocarbons (PFCs) are found in sources including aluminium production, refrigeration, and air conditioning; they are not produced in nature. PFCs exert 6 500 to 9 200 times the greenhouse effect of CO2.

Did you know?

That the greenhouse effect is critical in providing conditions suitable for life on Earth? Without it, the Earth's average temperature would be −19°C instead of 14°C. Conversely, too much CO2 could result in conditions such as on Venus that result in the temperatures exceeding 400° C or like on Mars whose thin atmosphere lacks GHGs and creates an environment too cold to be suitable for life.

The atmosphere is only composed of 0.03% carbon dioxide, and levels of CO2 have increased by 30% since 1700. The main source of carbon dioxide appears to be the burning of fossil fuels.

In order to stabilize atmospheric concentrations of greenhouse gases where they are today, global CO2 emissions would have to be cut by 50 to 60%.

Impact of Climate Change:

Think about these questions before watching the following clip: How have temperature, precipitation, ice, and seasons changed

in the arctic? What has the effect been on the land, sea, animals, and human

activities? Watch the clip titled Inuit Observations of Climate Change.

Canada has experienced warmer average temperatures with a 1.4° C increase from 1948 to 2007. The northern and arctic areas experience the coldest and driest weather in the country, and global warming is expected to impact them. The temperatures have already increased by 2.1°C in both the Yukon/North British Columbia mountains region and the Mackenzie District. The following map indicates a greater increase in temperature in the northern arctic regions.

The expected changes in Canada include:

warmer winters; tree line and wildlife species shift to the north; more frequent heat waves; changes in general weather patterns (precipitation, winds, and temperature); permafrost melting in the arctic; increased frequency of storms; glaciers retreating; greater risk of icebergs off the coast of Labrador; arctic sea ice melting changes to Inuit way of life and opening up year round ice free shipping routes; sea levels rising; and more severe drought conditions in the Prairies and B.C. leading to a loss of crops and

forest wildfires.

Dealing with climate change

The Kyoto Protocol is the world's primary agreement on trying to reduce global warming. More than 160 countries have signed the agreement; however the United States, the largest greenhouse gas producer, has yet to ratify the treaty because they feel that it is unfair that large population centres such as China and India have been exempted because they are classified as developing countries. In 2002, Canada ratified the Kyoto Protocol and committed to lowering GHG emissions to 6% lower than the 1990 GHG emissions (estimated at 596 megatonnes) by 2008-2012. However in that time the emissions had increased by 25%, and in 2005 the emissions were at 747 megatonnes – 32.7% above the Kyoto target.

Two strategies for dealing with climate change are:

Adaptation: This is the response to the changing environment by reducing our susceptibility to the impact of climate change. For example the location of activities such as ice fishing can be changed.

Mitigation: This is the active effort made to reduce GHG emissions locally and globally.

Review

What are greenhouse gases and the greenhouse effect? Compared to carbon dioxide, methane is 21 times better at

absorbing the emitted infrared radiation from the Earth. Why is the reduction of carbon dioxide emissions the focus of policies?

Which greenhouse gases are naturally produced? Which area of Canada will be affected the most by global

warming? What are three of the effects expected or being felt in this region?