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Global Warming, Decline in Fish Stock Could Damage World Economy

November 3, 2006 at 4:26 PM EDT

RAY SUAREZ: There were two especially grim reports on that front that grabbed headlines this week. The latest was published in today’s issue of the journal Science. A study predicted the current state of over-fishing, pollution and other factors will cause a global collapse of fishing stocks by 2048.

The study was global in scope, based on data from dozens of studies, and forecasts the bleakest timetable to date. For the record, the study was funded by the National Science Foundation, an underwriter of the NewsHour.

For more, we turn to Richard Harris, science correspondent for NPR. And, Richard, at the end of this time line, were they really projecting fishless oceans?

RICHARD HARRIS, Science Reporter, National Public Radio: Not exactly. What they were actually doing was looking at what the trend is right now in the decline of fisheries. And they said, “What if we just took this line and sent it down to zero? Where would it hit zero?” And the answer was 2048.

It actually wasn’t even the purpose of their study at all. It was a parenthetical clause of the study, but they thought, “Well, this was a good way to bring attention to the study,” because the decline doesn’t mean no fish left, but it means fish in such small numbers that they probably aren’t worth going after, in that sense.

But I’d like to step back a little bit and talk about what the study really was intended to do, which wasn’t to be looking at the future and the grim future of the ocean, in that sense. It was looking more broadly at why we should care about the ocean, why we should care about the diversity of life for the ocean.

And they really set out to say, “OK, everyone who scuba dives or whatever appreciates having beautiful, colorful fish of all sorts and all natures in the coral reefs.” And environments presumably do a lot better if there are a lot of different species and not just a monoculture of species there.

But what can we say about what that means for human beings? And why should people beyond scuba divers care about this? And that’s how this discussion started getting to other things that we care about, namely how many fish there are in the ocean that we might actually want to extract.

Decline in number of fish

RAY SUAREZ: Did they identify specific causes for driving down the number of fish in the sea?

RICHARD HARRIS: Well, there are obviously big causes in over-fishing right now; that's a huge thing. But the environment is also changing. They didn't focus so much on that, but we can enumerate the fact that there's runoff from the land that is hurting coastal areas. And, of course, coastal areas are places where the marine fisheries sort of, you know, lay their eggs and they do all that stuff. And those are very important areas, as well.

Also, as it happens, climate change not only is changing the atmosphere in terms of how much carbon dioxide in the atmosphere, but how much is in the ocean, and that's changing the acidity of the ocean. And that also has an effect on marine life, as well. So the ocean's getting it from a lot of different directions right now.

RAY SUAREZ: It contained a bleak forecast, but did it conclude by saying there was time to turn it around, things that humankind could do?

RICHARD HARRIS: Sure. In fact, the forecast is really more of a protection thing. If we just let the trend go, we aren't just letting the trend go. People are aware that you have to manage fisheries, and there are plenty of examples of fisheries that are not declining like that, that fisheries that are holding their own, because we are saying we shouldn't just fish them until there are none left. We should manage them.

And that is happening in some quarters. You know, it's a good news and a bad news story, clearly, because there are fisheries that are suffering terribly, as well. But what they're basically saying is, "Let's pay attention to these ecosystems and make sure that we are maintaining the diversity of life in the oceans, because that's one thing we can do, that will come back and help maintain healthy populations of fish."

Costs of global warming

RAY SUAREZ: Now science story number two. Earlier this week, a report by the British government warned of a devastating economic toll from global warming if it's left unchecked. After reviewing a series of other studies, economists estimated that greenhouse-gas emissions could cost nations 5 to 20 percent of their gross economic product if more dramatic cuts were not taken soon.

The paper also reported average global temperatures would rise in the next 50 years, contributing to drought, flooding and famine. And, Richard, has the government of a large, industrialized country -- the government, not an independent scientific group -- ever come out with a study like this?

RICHARD HARRIS: Well, I think that the British government has long been on the record saying global warming is a very serious issue and we need to do something about it. I think what they did was they took their own economic experts and they said, "This time, let's try to put together a document that will really convince the rest of the world of a position that we've been holding for a while."

And it's a 700-page document. I have not read it all, but it is full of very credible economic analyses and so on. And the idea is to try to convince people that this really is an urgent problem that we should take care of.

RAY SUAREZ: So it's right to put a dollar cost, what, on doing nothing, if we, like the fish study, do nothing, what happens?

RICHARD HARRIS: Absolutely. And that was their first big number, was, if you don't do anything, the assumption is, well, we'll all just get along and adapt and so on. And maybe that's a strategy that some people are thinking about pursuing.

These guys say, "No, if you don't do anything, it's actually going to cost a heck of a lot." And then they turned it around and said, "OK, what is the cost of doing something?" And they came to the conclusion it costs less to do something now than to wait and pay the piper, if you will, as these economic issues build up on us.

And, you know, droughts and, you know, famines, things like that, that would really hurt the developing world, in particular, much more than it would hurt us.

RAY SUAREZ: But those were the examples of the kinds of things that were going to cost money...


RAY SUAREZ: ... the change in the ecosystem, having a real economic cost on people's day-to-day lives?

RICHARD HARRIS: Right, more storms, for example, more droughts, more difficulty in growing crops, because it becomes less predictable. The spread of disease, particularly in tropical areas, is predicted to change as the globe warms. So all of these things can add up.

Of course, different economists have different ways of adding these up, but this was the way the British government put it together and came up with a very big number saying, "Look, guys, we ought to do something now."

Educated guesswork?

RAY SUAREZ: It also came up with a cost of doing something about it that was much smaller than the potential impact, right?

RICHARD HARRIS: Right, that's right, and it all depends really on what kinds of assumptions you make. When you're forecasting things that will be happening 50 to 100 years in the future, it's really hard to predict what's going to happen that far out, so you have to make a bunch of assumptions.

And partly how you choose your assumptions determines what your outcome is going to be. And they had some pretty grim assumptions about how bad the climate would be -- there are certainly a range of possibilities of where we could be in 50 to 100 years -- and then they had some fairly optimistic estimates about how much it would cost to do something about it.

But, you know, who's to say who's right and wrong? You really can't say here.

RAY SUAREZ: So, in short, some of this was educated guesswork?

RICHARD HARRIS: Of course. Well, what can you do, if you're an economist and you're asked to predict what something is going to be like 50 years from now? It's going to be guesswork. And it will be educated, in the case of these guys, who are, you know, first-rate economists.

RAY SUAREZ: But word of a record number of greenhouse gases being emitted this past year doesn't do anything to detract from their finding?

RICHARD HARRIS: Well, that's true. And one problem is that we are heavily dependent upon fossil fuels. And that's where the greenhouse gases come from, by and large, some deforestation, as well. But we have not yet come to grips with how to change that. So that's where we are right now.

RAY SUAREZ: NPR's Richard Harris, thanks a lot.

RICHARD HARRIS: Nice to be here.