CHIDONG ZHANG: Next lightning talk is given by Dick Feely on ocean carbon [INAUDIBLE]. 

DICK FEELY: It's a pleasure for me to talk about our ocean carbon program. This is a group of core PIs, one postdoc and 13 scientists, engineers, developing the highest quality carbon measurements for the global oceans. And our goal is to determine the signal of the anthropogenic signal carbon in the ocean and its perturbations. 

Our overarching question is, how does the ocean carbon cycle affect humankind's ability to predict and respond to climate change and its impacts, such as ocean acidification? Over the last two and a half centuries, we have seen that the anthropogenic carbon input to the atmosphere has been about 2.6 trillion tons of carbon. And the oceans have taken up about 600 billion tons of carbon. 

And if it wasn't for that ocean uptake of that carbon, the atmospheric concentration of CO2 would be about 500 parts per million right now. And we would be seeing about a half a degree warmer. So the ocean played a very significant role in this process. 

Our major questions are, what is the partitioning of CO2 between the land, the ocean, and the biosphere? And what are the controls of the seasonal to decadal variations of CO2 uptake and transport in the oceans? Where uptake is taken up, where does it go? And how is the ocean uptake of anthropogenic carbon affecting the ocean ecosystems and the atmosphere? So those are the questions we're addressing. 

Now the way we approach this is we work internationally with our international partners, through the SOCONET effort and at the global level. This is an array of moorings, 38 moorings on our part. Ships of opportunity, research ships, provide CO2 data to the ocean carbon project. And through the GLODAP project and the SOCONET project, we provide a global understanding of the surface ocean exchange of CO2. And then through the GO-SHIP program, we determine the full anthropogenic concentrations from surface to bottom in all the ocean basins. 

So we have both the understanding of the air-sea exchange and the transport in the oceans using this approach. We do this through our international partners. And at the national level, we work with the National Science Foundation, NASA, and NOAA. And within NOAA, we work between AOML, PMEL, and the Geophysical Fluid Dynamics Laboratory. So what we have been doing is accumulating these data sets on decadal timescales. And this is an example that Greg pointed out. 

So we collect data on these transect lines every 10 years. We then determine the anthropogenic CO2 in the ocean basin by interpolation between the lines. Then what we can see here is a perfectly good example of three decades of oceanic CO2 inventory in the Pacific. And what we can see is that we can now take the information between one decade and another decade, and then the other decades. So we can get the actual changes in inventories over time. 

Now, we have done this for the Atlantic and the Pacific now. And so from 1995 to 2005, we see that the Pacific has taken up about 8.8 petagrams of carbon. And then between 2005 and 2015, it's taken up 11.7. So it's accumulating its rate of uptake from one decade to the next, with most of that uptake in the Pacific being in the southern hemisphere relative to the northern hemisphere. 

In the Atlantic, we find that, again, there is this increase in that uptake of 5.1 to 8.1 petagrams of carbon. But most of that uptake in the Atlantic is in the northern hemisphere rather than in the southern hemisphere. So we are seeing differences between the ocean basins. 

Now the uptake that we are seeing, the 11.7 petagrams of carbon for that decade, plus the 8.1 for the Atlantic, is equivalent to all of the carbon released into the atmosphere by North America and South America combined over a ten-year period. So this uptake is really important to the global carbon cycle. So what we have done then is to provide an animation of that process. This is the work of Brendan Carter.

And you can see the filling in of the anthropogenic carbon, primarily in the subtropical regions where there is overturning circulation and deep mixing. And what we see is that carbon is taken up to the high latitudes, they're transported towards the equator, and they're subducted in the subtropical regions. And so we see the major build-up in the subtropical regions. 

This is due to a combination of air-sea exchange, as well as the enhancement of the ventilation process and overturning circulations in these regions. Same thing is true for the Atlantic. So now what we can do is we can compare the observations and the models together to see what the long-term rate of uptake of anthropogenic carbon is. 

It turns out that we are seeing a rate of uptake of between 2.5 and 3.0 gigatons of carbon, with an uncertainty of about 0.5. The ocean data gives us another point on that, with less uncertainty. It gives us an indication that the high rate of uptake is indeed correct. And that uncertainty is about 0.3, so that is very important. 

So the next decade of work is going to be certainly important for us. But the total uptake of anthropogenic carbon is about 170 petagrams of carbon, plus or minus 20. So our future direction is to focus on reducing these uncertainties as much as we can by enhancing the technology for carbon measurements. And Adrienne Sutton will provide us a tour of those new technologies we'll be developing, and then to determine how biological processes will be impacted by these changing chemistry. Thank you. 

[APPLAUSE] 

AUDIENCE: Let me ask one question. I think it's even a request to all the speakers. So I'd like to see these presentations put into a tiny bit of context. I love your lead-off speaker, who said, we are the biggest provider in the world of this information. So the question for you, and really, for everybody else who you give these presentations, if you weren't doing this work, could we make those estimates at all? If we could make the estimates, is your material adding-- are you a leader in this, and that nobody else could do it as well, our estimates would go way down? Or are you just a very confident contributor-- 

[INTERPOSING VOICES] 

DICK FEELY: I'm glad you brought this question up, Steven. There's a very important thing I want to add. NOAA provides 50% of the surface ocean measurements that we make. NOAA provides-- and in association with the National Science Foundation, working together, provides-- 50% of the GO-SHIP measurements that we make. So the majority of measurements [INAUDIBLE] we've just been talking about in terms of carbon are done jointly between NOAA and NSF. 

AUDIENCE: Because my perception-- I want to know if this is the correct perception-- that if PMEL disappeared off the map tomorrow, that those carbon estimates that you were talking about there could still be made, but I wouldn't trust them. 

DICK FEELY: You would be left with the models, which could no longer be validated by the observations. That's what you would be left with. The problem is, if you go back to that slide, you'll see the models diverge tremendously between each other. 

It's the observations though that provide a validation for this model. The original models were showing a flattening of this rate of uptake, which means that the oceans weren't taking up enough. Therefore, we would have a much more difficult climate change problem. But between the observations that we have seen, we have been able to focus the output of the models. And they're now working much better. 

AUDIENCE: So [INAUDIBLE] all these things are just by context. How unique is what you're doing? How critical is what you're doing? And if you stop doing it, what would we, as a society, lose? 

MICHELLE MCCLURE: OK. 

DICK FEELY: Thank you, Steve. That's a great question. 

[INTERPOSING VOICES]. 

MICHELLE MCCLURE: So Mike gets 10 seconds [INAUDIBLE]. 

MIKE MCPHADEN: In the Global Tropical Moored Buoy Array, there's no other place that can do that. I mean, we have the conversations, scientific leadership, technological acceleration, and NOAA infrastructure for making long-term measurements. And so this would not exist without this labratory. 

CHIDONG ZHANG: Well, this will be a very nice topic for discussion after the talk.