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Climate Change Causing Massive Shifts in Marine Ecosystems

Richard Kirby of the Marine Biological Association says the worst case scenario is a greater disruption to marine life than has occurred in the last 3 million years


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SHARMINI PERIES, EXEC PRODUCER, TRNN: Welcome to The Real News Network. I’m Sharmini Peries coming to you from Baltimore.

A recent study published in the scientific journal Nature Climate Change reveals that climate change, particularly global warming, is disrupting marine ecosystems on a scale that hasn’t been seen in 3 million years. Global warming of the earth is causing its waters to warm, and this could be causing the species to migrate to cooler waters, triggering drastic changes in ocean biodiversity. However, the authors of the study say that the effects on marine life can be curtailed with a reduction in greenhouse gas emissions.

Here to discuss this is Richard Kirby. Dr. Richard Kirby is joining us from Plymouth, UK. He’s a plankton scientist and associate fellow of the Marine Biological Association. He’s the author of this research report. Welcome to The Real News Network, Richard.


PERIES: So Richard, let’s start with you explaining to us the findings and how you came to the conclusions about the future impact of climate change on marine animals.

KIRBY: I’ll begin by saying something that people are probably very familiar with. It’s often said about the rainforest, that we know very little about the biodiversity of the rainforest. And that’s somewhere we can go easily. Relatively easily. People have been going to look at the rainforest for a long time, yet we still don’t think we know very much about the biodiversity. New species are still being discovered.

Now, the oceans are vast. They cover about 70 percent of planet earth. And we estimate there are probably about 2 million species in the ocean, of which we only know about 200,000. so we only currently know about 10 percent of all ocean biodiversity. That’s what we believe we know. And that sets us a problem for when we’re trying to understand how the biodiversity may reorganize with changes in its environment.

And so in this paper what we did, we created a model that enabled us to create artificial species, tens of thousands of artificial species, that we could populate the oceans with, and let them interact. We gave them an ecological niche that was based upon temperature, and from that we built communities. We then altered the temperature and saw how those artificial species rearranged themselves in the global ocean as their environment changed.

Now, that’s, that was a theoretical model. So we then tested that model against distributions of present-day species. Plankton, copepods and krill, fish such as tuna and sharks, and whales, cetaceans. And then we also looked at past organisms that had been preserved in the fossil record, and tested the model against those to see how well it predicted where organisms would occur in the oceans. And we tested that against foraminifera, a type of protozoan plankton that builds a shell around itself. And they preserve very well in the sediments because of the shell they have. So we have a fossil record of foraminifera.

So we tested our model, and it behaved very well at predicting where species occur in the oceans. And so then we applied different climate change scenarios and looked how that model would predict where the species would move to, or whether species would change in abundance over different climate scenarios.

PERIES: So Richard, have you got a good sense of how animals are already affected thus far due to climate change?

KIRBY: In terms of the model, it gave a good appraisal of how species are moving around in the oceans. But I’ll give you one stark example that wasn’t in our paper, but is well-known from research that we’ve done already. Particularly one of the other authors on the paper, Gregory Beaugrand. We’re in Plymouth, I’m in Plymouth in the UK. And so our closest waters are the Northeast Atlantic. And with plankton scientists, and we’re predominantly interested in the plankton because they underpin the whole marine food chain and they also occur at the surface of the sea, which is the region of the sea that is responding to climate change, because it’s overlaid by the atmosphere, which his warming. So the sea surface is soaking up the heat, and so it’s changing in its temperature already.

The Northeast Atlantic, off the coast of France, Spain, and the UK, has warmed by about three quarters of a degree C, Centigrade, over the last 50 years. Now, most people are probably familiar with the fact that animals and plants have particular thermal temperature [inaud.] that they’re adapted to, where they best like to live. Some animals like to live in hot places, other species like to live in cooler places. And if you look at the sea, the sea changes in temperature from the poles to the equator. It’s warmer at the equator and it’s cooler at the poles.

So from the equator to the poles you have a change in the species that occur. You have cold-loving species towards the poles and you have warm-loving species towards the equator. Now, if we very crudely divide those types into two types, cold-loving species and warm-loving species, obviously it’s not as simple as that. You have all types of temperature–but if you just crudely divide it into cold and warm-loving species, and we say that those species change from warm types from the equator in the tropics to cold types near the poles. And where they meet there’s a boundary. So we have cold types to the north, warm types to the south, and there’s a boundary where they change from one type to the other.

So if we look at where that boundary–we’re talking the plankton here, the creatures that drift at the sea surface that underpin the food chain. If we look where that boundary has occurred over the last 50 years, and given that the sea surface has warmed in the Northeast Atlantic over the last 50 years, then it wouldn’t–then the average, a reasonable person might say well, that boundary’s probably moved over the last 50 years, and it’s probably moved north as the temperature’s warmed. So warm species have moved north, and cold species, cold-loving species have retreated north. And they have.

And I often ask people, how far do you think that boundary might have shifted in the last 50 years? And people may say, oh, 25 miles, 25 kilometers. I say well no, no, be a little bit more ambitious. And they say well, maybe, maybe 100 kilometers. Or 100 miles. It’s shifted by 100 miles. Well actually, that boundary, if you were to make it a boundary, has shifted by 1250 kilometers. Ten degrees of latitude over the last 50 years. So the community of plankton has moved northwards by ten degrees of latitude as its habitat has warmed.

And these creatures underpin the food chain. So if they move then the food moves for higher creatures such as fish, for example. So they follow the food. So we have a reorganization of the marine ecosystem.

PERIES: Now Richard, you have also mentioned in your report that a reduction in greenhouse gas emissions can prevent a lot of these occurrences and the damage that it could be causing. How did you make that determination? How do we know how much of greenhouse gas reduction can preserve marine life?

KIRBY: We already have models that estimate the changes in temperature that different amounts of warming will have on the earth with different levels of carbon dioxide in the atmosphere. And we use those–ranging from about half a degree C warming to about 4 degrees C warming over the next 100 years–to look how the species would reorganize over different temperature regimes.

And we found that if we can keep global warming to below 2 degrees Centigrade, well below 2 degrees Centigrade, which is already been set by international bodies as the temperature threshold beyond which we will start to see significant changes to marine and terrestrial ecosystems. That if we keep it well below that, then the movements of organisms in the oceans won’t be much greater than we see on an annual basis seasonally anyway. So those effects may be benign, if we can limit climate change to below 2 degrees C. So that’s really the take-home message of the paper. We really need to take action on making sure we do something to limit climate change.

If, however, we do nothing and the worst case scenario pans out, and we have maybe a 4 degree C increase in global temperatures, or maybe a 5 degree C increase in global temperatures, then we could see a reorganization of marine life that’s greater in more of the ocean than occurred either between the last glacial maximum and today or the mid-Pleistocene and today. And the mid-Pleistocene was 3 million years ago, which is the headline that you gave at the very beginning. So we could see, if we don’t do anything, a reorganization, a change in species distribution, and a change in their abundance that’s greater than that that occurred over the last 3 million years.

PERIES: And your best guess at, if we are successful in Paris in terms of coming up with an international plan to reduce carbon emissions, will that have a, if it’s implemented and if it’s implemented well, do you think it can have a greater effect in reducing the changes in biodiversity of the marine life?

KIRBY: All this is very difficult to say. But it is the best thing we can do. We do need to limit global warming. It is having a large effect on the distributions of animals and plants on our planet, upon which we depend. We often say–well, people often–it’s very easy as a human and a terrestrial species to forget some fundamental things. We are unique amongst living organisms that we engineer, we engineer our environment, to live over a broad range of environments that we wouldn’t naturally live over, by virtue of the fact we can make clothes and we can sew animal skins together, we can clothe ourselves, we can live at high latitudes. We can make air conditioning, we can make central heating. We can live over a broad range of temperatures.

Most life on earth, all life on earth apart from us, lives where the environment suits it. Lives for the environment to which it has evolved. If that environment changes the life will move to an environment that suits it better. And we are, we rely upon all the ecosystem services that life on earth creates. All the little bugs, everything in the soil that cycles nutrients. Everything in the oceans that cycles nutrients. The oceans play a fundamental role in regulating climate through the carbon dioxide that they draw out of the atmosphere. If these start to change, then the whole ecosystem changes, of which we’re a part. I often tell people that we are a part of nature, not apart from it. We are intimately related to all life on earth. And if that starts changing apace, then will we be able to adapt or acclimate or change our way of life quickly enough to avoid the consequences?

PERIES: Richard, earlier you referred to a differentiation between what is the natural order of things and how things in terms of marine life might be naturally changing as opposed to exasperated by climate change. How do you determine the difference?

KIRBY: Well, between–in the model? Or just by looking at the species that are in the oceans today?

PERIES: In the model, as well as in its application.

KIRBY: Well in the model, we created these artificial species based upon temperature, and we gave them a niche, and they were allowed to interact and settle out, and populate the oceans depending upon the distribution of temperature. And then we looked, we compared that to what we see with living organisms today, and how that changes on an annual or a [decadeal] basis.

PERIES: And the impact can clearly be mapped in terms of global warming, then, according to your study?

KIRBY: Yes. For example, if global warming exceeds, or approaches 2 degrees Centigrade, the dangerous threshold being benign, below, and having large effects on the marine ecosystem, above, then the model predicts that tropical regions, the tropics will see a net loss in biodiversity. Some species may become more abundant individually, but there will be a net loss of biodiversity, whereas the poles will see an increase in biodiversity by about 300 percent. Three times the biodiversity present.

And that may be seen as a good thing, but the poles are, it’s a very different environment to the tropics. It’s a much smaller habitat, for example. Day length is very different. Photoperiod is very different. The seasons are very different. We don’t know how increasing that biodiversity will increase how species react, or interact, with each other.

So these reorganizations are very unpredictable, unknown, and we just don’t know the consequences. All we can say is that there are going to be significant effects in the oceans if we don’t keep global warming to below 2 degrees Centigrade.

PERIES: Richard Kirby, thank you so much for joining us and giving us the results of your study, and we hope to follow this and hope to have you back in the future.

KIRBY: It was a pleasure. Thanks very much.

PERIES: And thank you for joining us on The Real News Network.


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