The Gulf of Maine has recently experienced its warmest 5-year period (from 2015–2020) in the instrumental record, according to a new report which draws on the latest research to answer some questions about what climate change will mean for the Gulf of Maine in about 30 years. The paper’s lead author, Andrew Pershing, says the impacts will be varied. Pershing was formerly at the Gulf of Maine Research Institute, and is now with Climate Central, and organization of scientists and journalists based in Princeton, New Jersey.
Andrew Pershing sat down with Morning Edition Host Irwin Gratz. This interview has been lightly edited for clarity.
Irwin Gratz: First of all, let me ask you about your reaction to the United Nations report that's just out that says the world has to stop dumping CO2 into the air by 2050 if it hopes to avoid the worst of climate change effects.
Andrew Pershing: That's a certainly a very scary report in many respects. I think the big thing is to see the scientific community use words like "virtually certain" to talk about many of the climate impacts that we've been worried about. I think, for me, what I really took from that also in many ways, the report isn't that different. These are things that the scientific community was talking about in 1990 and 1995, when the first IPCC reports came out. So it's clear what we need to do, and we just need to get on it.
Let's get into some more of the specifics from your review paper. One of the things I noticed is it mentioned that, as changes occur, they'll lead to both warmer and less salty surface waters, but a greater salinity in the deeper ocean. Why is that important?
One of the things that we think about in oceanography is the stratification of the water. So if you have light water on top of heavy, dense water, it's really hard for nutrients that are stored below to mix to the surface, it's really hard for the cold water that's below to mix to the surface, and it's also really hard for oxygen to mix from the surface down deep. A more stratified Gulf of Maine has a very different Gulf of Maine, because it's potentially less productive, [and it] will change when the productivity happens, and then this big wildcard that I think the oceanographic community is just getting switched on to is oxygen. So what happens as we reduce oxygen levels at depth? What impact is that going to have on the community? That's one of the things we really highlight in the report is something we need to look at.
It also talks about the possibility of species declining or perhaps shifting in their areas. So maybe no more cod, but also more black sea bass and squid in the Gulf of Maine. Can the 2050 regime sustain the same level of economic activity from fisheries that we have now?
Yeah, that's a really great question, and I think that's something where there actually is some reasonably good news in that if we do many of the, kind of competent, informed fisheries management that the world has been working for for a long time, and the U.S. and New England has really led the way on many of these efforts, that we can have very productive fisheries. So lobster may not be at the boom that it is right now, but a lower lower CO2 world will still have a valuable lobster fishery in Maine. Black sea bass is a valuable species that in some cases, pound per pound, it can be as valuable as lobsters so that has the ability to make up for some of the economic losses.
There has been one temperature based study that projects that lobster stock will decline as much as 50% by 2050. But your new report indicates other work using other methods that lobster abundance could increase in deeper waters farther offshore. So what does that mean for lobster fishermen, maybe things won't be so bad?
We have several other studies that give or have some nuanced about story that maybe there's potentially more of a shift into deeper water, not quite sure that lobster can produce baby lobsters at the same rate if the population is offshore, especially with some of these stratification effects that we talked about. But this is an area to really watch.
The research talks about the Gulf of Maine possibly acting as a refugee. Is it possible the Gulf could serve that purpose for the endangered right whale?
Absolutely, and that's one of the really interesting things that we have when you start to look at the Gulf of Maine in the context of the of the whole ecosystem of the Northwest Atlantic is that the Gulf has a lot of really unique features that may allow it to hold on to more cold water, and therefore more cold water species, perhaps longer.
