The last century was the warmest in the past 1,000 years, and the 1980s and '90s were the warmest decades on record. Scientists predict that average temperatures could rise by as much as 5.8∞C, or 10.4∞F, by the end of this century. What's wrong with warmer temperatures? One consequence we seem to be experiencing already is an increase in natural catastrophes like floods, tornadoes and droughts. Isztar Zawadzki, director of the McGill Radar Observatory and a professor in the Department of Atmospheric and Oceanic Sciences, studies "extreme weather." We asked him what's going on.

Is extreme weather a new scientific term?

It is a new one; I remember using it for the first time a couple of years ago.The term is correct because variability is a big factor in the weather, and extreme weather refers to extreme variability. Always, whatever record you are currently breaking, you will break it again. We constantly hear about colder weather than ever in the last 50 years, or hotter than ever in the last 50 years.

The term is being used more often for two reasons. First, weather variability has more impact now than before; that's the social connotation of the term. Second, with the change of climate we are seeing, there is a possibility that variability will increase even more. That's the scientific connotation.

Are incidents of extreme weather increasing?

It's hard to say whether they are increasing, or whether we are more sensitive to it. Our records of weather are not that long, so even if we had ice storms in the past, it would not have had the same impact as the 1998 ice storm in Quebec and Ontario. This time it had a huge impact because we are so dependent on electricity; the power lines broke down, and we all suffered. But 100 years ago, it would have been nowhere nearly as severe. During the ice storm I went to my house in the country and I saw people adapting very rapidly over there.

So increases in population have an effect?

Disasters caused by weather are increasing with time, and there is an excellent correlation with increases of population. Larger concentrations of population means that extreme weather is more likely to cause a disaster. But we don't have enough objective records of these events from the past. Today, the number of people observing them is greater. It does not mean that the phenomenon itself is more frequent. We have used radar to observe these events for less than 20 years, so how can we compare extreme weather now with the past? The only thing we can say for sure is that we feel extreme weather is increasing.

Will extreme weather increase because of global warming?

There is a good possibility that that will happen; fluctuations in the weather will likely be stronger. The global climate system is getting out of equilibrium and will undergo more variability before reaching a new equilibrium. Many elements in the system will be forced into a fast adjustment, and that will create oscillations in the weather.

How long will it take to reach a new equilibrium?

It could take 200 years, or 1,000 years. It depends on how fast everything can adjust to the new conditions. But species need time for evolution, for change. If the climate is changing too fast, there won't be time for a proper adjustment.

Is there a scientific consensus today about global warming?

We can say with certainty that global warming is happening; it is a fact. We have seen global warming for over a century now. With less certainty but still some confidence, we say that it's happening because of our own activities. There is still a debate on whether we are the cause, but there is a growing consensus that we are. Certainty stops at the level of global effects. At the regional level, the certainties drop even more. And when we talk about weather and extreme weather, we have zero certainties.

What are the likely effects of global warming in a climate like Canada's?

The effect in the east of Canada and the west of Canada could be quite different. In some scenarios, it would actually be colder in Quebec. Global warming doesn't mean that everyone will have higher temperatures; it means we will have higher temperatures overall around the world.

Are we complacent about global warming, maybe hoping that it will warm up the temperature here?

Canadians are generally concerned about the environment, but yes, I think there is a hope that maybe it won't be so bad here in Canada. That's not necessarily true, however. Global warming is global; regionally, we don't know what is going to happen.

What parts of the world might be affected most?

It is hard to answer that because it is very speculative. But I can say that if global warming continues, extreme weather will not be the biggest problem. The melting of the ice caps will be the big disaster. Coastal regions will be inundated, and some countries may disappear. Vietnam, for instance, will be covered by water. Another potentially disastrous outcome could be desertification of regions that are fertile today, with severe consequences for food production. Maybe other regions could compensate for the loss of food production, but that is a big if.

Is there hope for implementation of the Kyoto Protocol (an inter-national treaty for the reduction of greenhouse gas production)?

The Kyoto Protocol sets relatively modest goals, but most countries have not implemented them. It would require such a rearrangement of our economic activity that it will be difficult to meet those goals, and it would not have a great impact on the climate. The main impact would be on our societies; if we do meet the goals, we will have changed our lifestyles in a way that is more compatible with stabilizing the emission of greenhouse gases, and that would be the most positive outcome. But reversing the warming trends in our climate will take much more than the Kyoto Protocol.

Are developed countries making any progress in reducing greenhouse gases?

There is a lot of resistance. People are not all that ready to make sacrifices, even for a good cause. We hope that we will be able to make the necessary changes, because if our worst fears about global warming are true, we are headed for doomsday. But we are not totally convinced about the worst case scenarios. We are trying to do better and move toward the Kyoto Protocol, but there is no sense of panic.

Should there be a sense of panic?

The price we would have to pay for a sense of panic would be as bad as the cause of the panic. Can you imagine our society now not relying on fossil fuels? What would it do to our economy and our daily lives? What if we had to go back to being cold at night in the winter? The adjustment has to be gradual. If we change abruptly, we will produce disasters as bad as the ones we fear from climate change. I don't think that people are inherently irresponsible; we're just inherently cautious, and that's probably not a bad thing.

You said that our society's transition has to be gradual. Why?

Our economies are sensitive to these kinds of adjustments. They are heavily dependent on oil; changing our lifestyle is not something we can do overnight -- we probably cannot do it over one generation. We need a careful balance; if we stopped using oil overnight, what would we use to power the industries which are essential to our economic stability? After September 11, people stopped flying, and that alone hurt the economy. Can you imagine what would happen if several industries suffered at once?

What about alternative energy sources; are we moving as fast as we should on that front?

We could always do more. What if we took all our health care dollars and put them into alternative energy?

We would make a lot more progress in that area. But again, we must balance the needs and conflicting interests of our society. Each scientific community clamours for funding for its research, but society has many priorities. Canada invests a lot more into social programs than into research; is that a good idea, or is it short-sighted? Many people today are asking if we should be living the way we are, or should we live in ways more friendly to nature? And how do we get there? These are not scientific questions, these are social questions.

Could global warming and extreme weather lead to the end of the human race, or could we adapt?

I think humans will adapt, but how many other species will? That is not certain, but whatever happens, we won't die off. We may go through a period of great upheaval, but we have shown throughout history that we are very adaptive. Humankind went through an ice age, through warm periods and cold ones, and we are still around, still making a mess. That is nothing new by the way; we have always made a mess in nature. In prehistoric times, nomadic tribes moved from place to place because wherever they went, they messed up the ecosystem. We are a destructive species; we need a lot, we take a lot, and the more intellectually agile we become, the more destructive we are. Our biggest responsibility is toward future generations. They are the ones who could face a much harsher reality.

What can we do to help? Learn more at www.climatechangesolutions.com.

Dr. Zawadzki was interviewed by Sylvain Comeau.