In 1975, this scientist warned us that global warming 'could be terribly important'

He predicted that the planet would warm, and he and lived to see his prediction come true. 

Geophysicist Wallace Smith Broecker died on Monday. He was 87.

In 1975, Broecker brought the term "global warming" into common use and predicted a not too distant future where humans would be forced to grapple with the extreme effects of climate change.

That same year, Broecker spoke to former As It Happens host Barbara Frum about his groundbreaking work.

From our archives, here is part of their conversation.

Dr. Broecker, I think every single scientist we've spoken to on this program for the past year has forecasting a cooling trend — maybe even a new Ice Age — and you're saying quite the opposite. Are the people who've been forecasting cooling wrong?

I think so. And I think we're due for another one of these warmings, natural warming, in the next 20 or 30 years.

How warm is a warming?

Well, the range of these variations has been about, plus or minus, one degree centigrade for the global average. But in the northern parts of the world it has been somewhat larger, in the polar regions.

Why is one degree even significant? That sounds like a margin of error you could be out by.

I think the big question is the rain fall patterns on the Earth are going to shift when you have this big a climate change and the question comes up in agricultural land, is the rain fall shift going to benefit agriculture or hurt agriculture.

Unfortunately, even with the rather elaborate computer modelling systems we have now, it's not really possible to say with any certainty. 

But you don't think the warming effect is going to come on us drastically then?

The CO2 warming trend, which is accelerating all the time because we're burning more fuel and more fuel every year, will take over and will push us, before the end of the century, or very early in the next century, beyond the limits of our natural experience.

In other words, the climate of the world will be somewhat warmer than it's been even at the peaks of the natural cycles in the natural cycles during the past 1,000 years or so.

And, of course, it's just going to continue getting ever warmer as we produce ever more amounts of CO2. Until we transfer to some other means of developing our energy than chemical fuels, I think we're in for consistent warming.

So when one talks about one degree centigrade as not being a very big climatic change, but then thinks back to the time when all of Canada was covered with ice and realizes that at that time global temperatures were only a couple degrees colder than they are now, one begins to see that the seemingly small temperature changes can have rather large environmental effects.

Is this more than just of academic interest? Is this a debate that's important to sort out?

Possibly, it could be terribly important. We're programmed into having six and a half billion people on the planet no matter what we do and I suspect that the pre cent of people starving is going to steadily climb because our agricultural capability is unlikely to keep up with our population growth.

And so we've become ever and ever more vulnerable in agriculture to climatic change or to just bad climatic years. 

So the more that we know about climate the better prepared we might be — if, indeed, one can prepare for things like starvation.

Written by Richard Raycraft and John McGill. Q&A has been edited by length and clarity.