Global Warming

1. What's the difference between greenhouse gases, global warming and climate change?
2. What's the distinction between weather and climate?
3. How serious is global warming?
4. Can we do something about emissions of heat-trapping gases?
5. What is the Greenhouse Effect?
6. What is global warming?
7. What is causing global warming?
8. Is global warming already happening?
9. Are humans contributing to global warming?
10. How much warmer is the Earth likely to become?
11. Would a temperature rise of a couple degrees really change the global climate?
12. The Impacts of Climate Change: Coming to a Planet near you!
13. Is there anything we can do about global warming?
14. Will responding to global warming be harmful to our economy?

1. What's the difference between greenhouse gases, global warming and climate change?

To understand climate change, we need to understand three widely misunderstood terms:

• Greenhouse gases;
• Global warming; and
• Climate change.

First, greenhouse gases are gases which prevent heat from escaping or trap it near the earth's surface.

As greenhouse gases increase in the atmosphere, this traps more heat which leads to global warming.

As the Earth warms up, this in turn affects the Earth's climate and leads to changes which are just beginning to be felt.

What's the distinction between weather and climate?

Two other terms, weather and climate are distinct, but interrelated, which are:

• Weather; and
• Climate.

Weather is what we experience on a daily basis, every day it rains, snows, is hot, cold, windy, sunny, or cloudy depending on where we live and what type of climate we live in: Climate, in other words is what drives the type of weather we experience in our daily lives and what we expect the weather to be like over the different seasons. When the climate we've adapted to changes, it affects can affect people's lives in a great way.

When we change the atmosphere we change the climate and the weather that our society and all societies in the world have adapted to.

When we think of the atmosphere, we think of it as too big for us to have any affect on. That may have been true at one time, but in the last hundred years or so, we've been very busy. The industrial revolution started it. We have been using the air that we depend on for life itself as a garbage dump.

2. How serious is global warming?

Global warming is one of the most serious challenges facing us today. To protect the health and economic well-being of current and future generations, we must reduce our emissions of heat-trapping gases.
Can we do something about emissions of heat-trapping gases?

Yes, by using the technology, know-how, and practical solutions already at our disposal, we can.
What is the Greenhouse Effect?

The "greenhouse effect" refers to the natural phenomenon that keeps the Earth in a temperature range that allows life to flourish. The sun's enormous energy warms the Earth's surface and its atmosphere. As this energy radiates back toward space as heat, a portion is absorbed by a delicate balance of heat-trapping gases in the atmosphere-among them carbon dioxide and methane-which creates an insulating layer.

With the temperature control of the greenhouse effect, the Earth has an average surface temperature of 15°C. Without it, the average surface temperature would be -18°C, a temperature so low that the Earth would be frozen and could not sustain life.

3. What is global warming?

Global warming refers to the rise in the Earth's temperature resulting from an increase in heat-trapping gases in the atmosphere.

4. What is causing global warming?

We are. Scientists have concluded that human activities are contributing to global warming by adding large amounts of heat-trapping gases to the atmosphere.

Our fossil fuel use is the main source of these gases. Every time we drive a car, use electricity from coal-fired power plants, or heat our homes with oil or natural gas, we release carbon dioxide and other heat-trapping gases into the air.

he second most important source of greenhouse gases is deforestation, mainly in the tropics, and other land-use changes.

Since pre-industrial times, the atmospheric concentration of carbon dioxide has increased by 31 percent. Over the same period, atmospheric methane has risen by 151 percent, mostly from agricultural activities like growing rice and raising cattle.

As the concentration of these gases grows, more heat is trapped by the atmosphere and less escapes back into space. Its this increase in trapped heat changes the climate, causing altered weather patterns that can bring unusually intense precipitation or dry spells and more severe storms.

5. Is global warming already happening?

Yes. The Intergovernmental Panel on Climate Change (IPCC) concluded in its Third Assessment Report that: "An increasing body of observations gives a collective picture of a warming world and other changes in the climate system."

The kinds of changes already observed that create this consistent picture include the following:

Examples of observed climatic changes:

Increase in the global average surface temperature of about 1°F in the 20th century;

The dramatic decrease of snow cover and sea ice and the retreat of mountain glaciers in the latter half of the 20th century;

Rise in global average sea level and the increase in ocean water temperatures;

A likely increase in average precipitation over the middle and high latitudes of the Northern Hemisphere, and over tropical land areas;

Increase in the frequency of extreme weather events in certain regions of the world.

Examples of observed physical and ecological changes

• The permafrost is thawing;
• The growing season is changing in middle and high latitudes;
• There is a Pole-ward and upward shift of plant and animal ranges, which is altering complete ecosystems;
• Extinction and the decline of vulnerable plant and animal species;
• Earlier flowering of trees;
• Earlier emergence of insects;
• Earlier egg-laying in birds;

6. Are humans contributing to global warming?

In 1995, the world's climate experts in the IPCC concluded for the first time in a cautious consensus, "The balance of evidence suggests that there is a discernible human influence on the global climate." In its 2001 assessment, the IPCC strengthened that conclusion considerably, saying, "There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities."

Scientists have found significant evidence that leads to this conclusion:

• The observed warming over the past 100 years is unlikely to be due to natural causes alone; it was unusual even in the context of the last 1,000 years.
• Climate models have become more sophisticated and new developments have helped to link global warming to human activities:
• There are better techniques to detect climatic changes and attribute them to different causes.
• Simulations of the climate's response to natural causes (sun, volcanoes, etc.) over the latter half of the 20th century alone cannot explain the observed trends.
• Most simulation models that take into account greenhouse gas emissions and sulfate aerosols (which have a cooling effect) are consistent with observations over the last 50 years.

7. How much warmer is the Earth likely to become?

The IPCCs (Intergovernmental Panel on Climate Change) Third Assessment Report projects that the Earth's average surface temperature will increase between 1.4°-5.8°C between 1990 and 2100 if no major efforts are undertaken to reduce the emissions of greenhouse gases (the "business-as-usual" scenario). This is significantly higher than what the Panel predicted in 1995 (1.0°-3.5°C), mostly because scientists expect a reduced cooling effect from tiny particles (aerosols) in the atmosphere.

Scientists predict that even if we stopped emitting heat-trapping gases immediately, the climate would not stabilize for many decades because the gases we have already released into the atmosphere will stay there for years or even centuries. So while the warming may be lower or increase at a slower rate than predicted if we reduce emissions significantly, global temperatures cannot quickly return to today's averages. And the faster and more the Earth warms, the greater the chances are for some irreversible climate changes.

8. Would a temperature rise of a couple degrees really change the global climate?

An increase of a few degrees won't simply make for pleasantly warmer temperatures around the globe.

Even a modest rise of 1.1°-1.7°C could have dramatic effects. In the last 10,000 years, the Earth's average temperature hasn't varied by more than 1.0°C. Temperatures only 2.7°-5°C cooler than those today prevailed at the end of the last Ice Age, in which much of Canada was covered by more than 1,000 metres of ice.

The Impacts of Climate Change: Coming to a Planet near you!

A wide range of the impacts of global warming are becoming apparent.

For example, there has been about a 40% decline in Arctic sea-ice thickness during late summer to early autumn in recent decades.

According to the Intergovernmental Panel on Climate Change (IPCC), just 2°C (of additional warming would suffice to take the world into the realm of risks to many ecosystems and a large increase in extreme events such as storms, floods and droughts.

A key finding of the International Symposium on the Stabilization of greenhouse gas (GHG) Concentrations (2005) was that research completed since the publication of the IPCCs Third Assessment Report has led to "greater clarity and reduced uncertainty about the impacts of climate change... In many cases the risks are more serious than previously thought."

Examples of impacts likely to occur during this century if GHG emissions are allowed to continue rising unchecked includes:

• Sea level rise sufficient to flood areas inhabited by millions of people;
• More intense rainfall events and tropical storms;
• Tens of millions of additional people at
  risk from coastal flooding and hunger,
  hundreds of millions from malaria and billions from water shortage;
• A significant proportion of land-based species "committed to extinction";
• A large-scale redistribution of species. Natural ecosystems are less able to adapt to change than are human systems.
• Additional annual costs: tens of billions of
  dollars for the world's water management,
  agriculture and forestry sectors;
• A decline in the extent of sea-ice around the North Pole in summer by more than 50% and a threat to the cultural survival of some Arctic communities;
• Destruction of more than half of the world's coral reefs; and
• In Canada, reduced water quantities from the Great Lakes to the Rockies.
• Trillions of dollars cost to world economy. (7 trillion, according to a recent Globe & Mail article).

9. Is there anything we can do about global warming?

Yes! The most important action we can take to slow global warming is to reduce emissions of heat-trapping gases.

Governments, individuals, and businesses can all help.

Governments can adopt a range of options for reducing greenhouse gas emissions, including:

• Increasing energy efficiency standards;
• Encouraging the use of renewable energy sources (such as wind and solar power);
• Eliminating subsidies that encourage the use of coal and oil by making them artificially cheap;
• Protecting and restoring forests, which serve as important storehouses of carbon.

Individuals can reduce the need for fossil fuels and often save money by:

• Driving less and driving more fuel-efficient and less-polluting cars;
• Using energy-efficient appliances;
• Insulating homes;
• Using less electricity in general.

Businesses can increase efficiency and save substantial sums by doing the same things on a larger scale.

And utilities can avoid building expensive new power plants by encouraging and helping customers to adopt efficiency measures.

10. Will responding to global warming be harmful to our economy?

Reducing our impact on the global climate does not have to hurt the world's economies.

The answer depends much on the "how" and "when."

The challenge is to strike a balance between responding early enough to avoid major negative (costly) impacts, and responding some time later in order to avoid taking big, expensive steps now which then may turn out to be unnecessary or inappropriate. This type of challenge is typical in business and industry; decision-making under uncertainty is the daily bread of most managers.

Clearly, global warming still involves many unknowns, but the remaining uncertainties in our scientific understanding no longer warrant a "wait and see" stance. Science tells us with increasing certainty that we are in for a serious long-term problem that will affect all of us.

And there is much we can do now that makes sense in terms of the economic bottom line while helping to reduce our impact on the global climate and on our local environment and health. The United States and other developed countries should seize the opportunity to take the lead in developing new, clean, energy-efficient technologies, and help developing countries take a greener path to economic prosperity. All of this can be done in a cost-effective manner, while creating jobs and new business opportunities.