Thursday, January 03, 2008

Temperature and CO2: A new figure for a new year

Last month, Science had a terrific review article on the threat that rising CO2 concentrations and rising temperatures pose to the world's coral reefs. Scientists, alas, are not great marketers. The plight of the world's coral reefs is a tough sell at a time when most North Americans are "holiday" shopping and powering all manner of coloured lights, inflatable Santas and animatronic reindeer (though the review did garner some front page and radio attention the week of publication).

In my mind, the most compelling feature of the paper was this one figure to the left (reprinted here without any particular permission, shhh). It is a simple inversion of the famous 420,000 year record of temperature and CO2 plots from the Vostok ice cores, shown in every climate change course, presentation and documentary. The very same data, plotted a different way: temperature vs. CO2, rather than temperature and CO2 over time.

I hope to see this figure used more often, whether in relation to coral reefs or not, because it clearly demonstrates three crucial points about the planet's current situation:

1. There is warming in the pipeline, like it or not. Today (pt. A) lies far outside the cluster of data points from the Vostok core. Those points represent a rough historical relationship between temperature presuming the climate is at equilibrium. Right now, we are experiencing what climate modelers call the transient response to CO2 forcing. If CO2 concentrations froze now, global temperatures would continue to rise until the climate reached equilibrium

2. That equilibrium point lies outside any experience the planet has had in the past 420,000 years, even without any future increase in greenhouse gas concentrations (as the current CO2 level is unprecedented). A further increase places the planet in an even farther outside the envelope of anything in the "recent" geological record, to use a geologists warped definition of the word recent.

3. Oceanic ecosystems - particularly coral reefs - that are sensitive to both the physical (temperature) conditions and the chemical (pCO2) conditions are already and will continue to experience a thermal and chemical environment not seen for hundreds of thousands of years. As I've said before, if you are a coral, pick your poison. This naturally raises the issue of what constitutes dangerous climate change, a key question tossed about a bit lately (see Climate Progress) that I will return to later.

Andrew Revkin, on his NY Times blog Dot Earth, has been asking what language, if any, can most effectively communicate the urgency of climate change, most recently using the idea of the "elevator speech" (Eli's is good). Is there one figure that tells the story best?



RE: "Andrew Revkin has been asking what language, if any, can most effectively communicate the urgency of climate change, ... Is there one figure that tells the story best?"

Can I nominate POLAR CITIES as a figure of speech that might speak to future generations, even though not everyone is on board yet? IPS news service just did the first media story about polar cities here:


''Dan Bloom thinks it's time to figure out how to build self-sustaining cities in the polar regions because climate change will eventually make most of Earth uninhabitable.

These polar cities may be "humankind's only chance for survival if global warming really turns into a worldwide catastrophe in the far distant future," Bloom told IPS.

Bloom isn't a scientist or any other kind of expert. A U.S. citizen in his late fifties living in Taiwan teaching English, he's lived all over the world as a reporter-editor, teacher-translator and author. And now Bloom wants to shake people out their everyday indifference to the great emergency of our age: climate change. ''

Simon Donner said...

Er, ok, though not exactly a figure.
are these floating cities? how about the figure showing the annual minimum extent of arctic sea ice?

Anonymous said...

Hi Professor,
No, these are not floating cities, but land-bound sustainable polar retreats, SPRs, or we could also call them sustainable population retreats, also SPRs, and cut out the polar part, because some of the survivors' cities might be in inland areas of major continents, high above coastline sea levels at that future time. But no, polar cities, as envisioned are not floating cities. And they not a prediction, just a thought experiment. Hopefully, humanity will never need them. However, things look rather bad. Iffy.

As for a figure, I am not a figure man, but I appreciate your blog and your erudition on these issues. I am looking for dying canaries in the coal mines, to warn of us of the seriousness of the problem, to help ring the alarm, sound the alarm, raise an alert. We all need to be "alerters" now, and try to get things settled ASAP. It might be too late already. Sigh. The die are cast. Dice? Die? Or it could be we have until 2015 or 2050 to fix things with the way we consume raw materials here on Earth and spit out consumer junk for the money markets. Maybe 2100 is the last date we can figure on. After that, if we haven't done our homework, it's curtains. The mother of all curtains.

Like your good letter to the future says: we need to act now! Polar cities is just a guerilla theater approach to wake people up. Now. Most of our neighbors are sleeping walking through all this, mesmerized by TV and computer games and a junk life. This long emergency is not a game. It is for real. We need important actions now, all across the board, all across the globe. Moi, Je fear the worst! But I remain hopeful and an eternal optimist.


Anonymous said...

Simon, it's a stunning figure. Thanks. Please don't let people distract you from continuing the discusion of ocean pH here, it needs serious attention (and likely will attract serious distraction).

Part of what's so hard about explaining this is -- people who don't believe in evolution don't believe stratigraphy, and it's the long deep cores through geologic time that give us the information about the past.

Maybe the pictures of the pteropods with their shells dissolving are the best illustration, post them along such a chart or as callouts to points on the line.

I'd avoid oversimplifying because, like temperature, the ecology doesn't feel the global average that humans like to work with, and the change in pH is going to be happening differently across latitude, and across areas of upwelling and sinking water, in bands and swirls.

It's worth reminding people that a lot of plankton are larval forms of organisms that become sessile adults, so exposure to water conditions that kill either younger or older forms off will impact the species.

The larval forms among the vast variety of plankton swim, and swim, and swim, until one day they start to mature, and their shapes change, and one end gets heavy, and they sink. And where they land, they may be able to creep around a bit, but soon that ability ends and they anchor where they lay and become adults.

Simon Donner said...

And it is not just pH, of course, but the changing carbonate chemistry, that will prove a problem for calcifying marine organisms like corals. The response of the carbonate chemistry will vary worldwide, with some pacific equatorial regions becoming more marginal for coral development sooner than other parts of the tropics.

I wish I could claim responsibility for the figure, but it comes straight from the Hoegh-Guldberg et al review in Science.

Hank Roberts said...

More news, not good:

... at the University of Delaware, Clinton Hare, led research published Dec. 20 in Marine Ecology Progress Series....
... The Bering Sea is highly productive thanks mainly to diatoms, a large type of phytoplankton.

“Because they're large, diatoms are eaten by large zooplankton, which are then eaten by large fish,” Hutchins explained.

The scientists found that greenhouse conditions favored smaller types of phytoplankton over diatoms. Such a shift would ripple up the food chain: as diatoms become scarce, animals that eat diatoms would become scarce, and so forth.

“The food chain seems to be changing in a way that is not supporting these top predators, of which, of course, we’re the biggest,” Hutchins said.

A shift away from diatoms towards smaller phytoplankton could also undermine a key climate regulator called the “biological pump.”

When diatoms die, their heavier carbon-based remains sink to the seafloor. This creates a “pump” whereby diatoms transport carbon from the atmosphere into deep-sea storage, where it remains for at least 1,000 years.

“While smaller species often fix more carbon, they end up re-releasing CO2 in the surface ocean rather than storing it for long periods as the diatom-based community can do,” Hutchins explained.

This scenario could make the ocean less able to soak up atmospheric carbon dioxide.

“Right now, the ocean biology is sort of on our side,” Hutchins said. “About 50 percent of fossil fuel emissions since the industrial revolution is in the ocean, so if we didn’t have the ocean, atmospheric CO2 would be roughly twice what it is now.”

Hutchins and colleagues are doing related experiments in the north Atlantic Ocean and the Ross Sea, near Antarctica. The basic dynamics of a greenhouse ocean are not well understood, he noted.

“We’re trying to make a contribution by doing predictive experimental research that will help us understand where we’re headed,” he said. “It’s unprecedented the rate at which things are shifting around.”

The researchers collected the algae samples from the Bering Sea’s central basin and the southeastern continental shelf. They incubated the phytoplankton onboard, simulating sea surface temperatures and carbon dioxide concentrations predicted for 2100.

Each of these variables was tested together and independently. Ratios of diatom to nanophytoplankton in manipulated samples were then compared with those in plankton grown under present conditions.

The scientists found that photosynthesis in greenhouse samples sped up two to three times current rates. However, community composition shifted from diatoms to the smaller nanophytoplankton.

Temperature was the key driver of the shift with secondary impacts from the increased carbon dioxide concentrations, according to the study.


Hutchins and Hare’s collaborators were Karine Leblanc of the Centre National de la Recherche Scientifique, in France; Giacomo DiTullio, Peter Lee and Sarah Riseman of the College of Charleston; Raphael Kudela of the University of California at Santa Cruz; and Yaohong Zhang of the University of Delaware.

Hank Roberts said...

Er, and I meant to say, to stay in line with your very good topic --

perhaps adding a couple of lines for the plankton population discussed, to the chart, would work? Not sure.

It's hard to compete with the stuff that's coming out as a result of scaring the economists lately -- like:

The ocean news is a lot worse, but these "grownups" don't understand nature matters.

Simon Donner said...

Hank - that new diatom study shows how much we still need to learn about the sensitivity of ocean biology to co2 / carbonate chemistry. There may be some surprises in store.

Anonymous said...

What happens when the cooling comes? The sun causes cycles in our weather systems and will do so again. I understand the concern abour CO2 but we have had concentrations at this level, and above, before.


Sir James Lovelock’s interview in the Guardian on Saturday — March 1, 3008 — and it is a must-read:

He says he writing a new book now, too. To fill us in on what comes next. I don’t know if I have told anyone here this, but last month I sent some images of my polar cities concept to Dr Lovelock by email, and he wrote back the next day, saying: “Thanks for showing me those images. It may very happen and soon.”

I know Dr Lovelock has not been knighted yet by the Queen and maybe never will be, so he is not actually a “Sir” as I kiddingly wrote above, but he certainly should be honored that way. Sir James Lovelock. Yes. Has a good ring to it.

His interview in Saturday’s Guardian will knock your socks off. NSFW. But a very important interview. Read it and weep. (And then get back to work again, doing what you can to try to mitigate the impacts of climate change on this unsuspecting Earth that has been so kind to us for so many years as to give us a home for many many generations now. Soldier on, all who know that global warming is for real!)

— Posted by Danny Bloom

Anonymous said...

Lance Ellersby showed an excellent connection between atmospheric CO2 concentrations and sea surface temperatures. Since the oceans contain approximately 50 times the concentration of CO2 that is in the atmosphere, this correlation may be quite revealing. This past year's ocean cooling may remove some CO2 from the atmosphere. That would be a first.