The Ocean’s Carbon Balance

From NASA’s Earth Observatory:

by Holli Riebeek • design by Robert Simmon • June 30, 2008

[WARNING: Beware of booby traps!]

The idea seemed simple enough: the more carbon dioxide that people pumped into the atmosphere by burning fossil fuels, the more the oceans would absorb. The ocean would continue to soak up more and more carbon dioxide until global warming heated the ocean enough to slow down ocean circulation. Water trapped at the surface would become saturated, at which point, the ocean would slow its carbon uptake. To oceanographers of 30 years ago, the question was less, how will human emissions change the ocean carbon cycle, and more, is the ocean carbon cycle changing yet?

One of the largest unknowns in our understanding of the greenhouse effect is the role of the oceans as a carbon sink. Much of the carbon dioxide released into the atmosphere by the burning of fossil fuels is soaked up by the oceans, but changes in the climate are altering this absorption in surprising ways. (Photograph ©2007 *Fede*.)
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The question matters because if the ocean starts to take up less carbon because of global warming, more is left in the atmosphere where it can contribute to additional warming. Scientists wanted to understand how the ocean carbon cycle might change so that they could make more accurate predictions about global warming. Thus motivated, oceanographers began a series of research cruises, trolling across the Pacific from Japan to California, from Alaska to Hawaii, and through the North Atlantic from Europe to North America. On shore, others developed computer models.

For more than 30 years, research ships have cruised the world’s oceans, measuring carbon dioxide concentrations, ocean temperatures, winds, and other properties. The map shows the paths of research cruises conducted as part of the World Climate Research Programme’s Climate Variability and Predictability project. Cruise measurements—along with those from buoys, drifting floats, orbiting satellites, and land-based weather stations—are beginning to reveal long-term trends to ocean researchers. (Map by Robert Simmon, based on data from Dana Greeley, NOAA.)

After 30 years of research, the question itself hasn’t changed, but the reasoning behind it couldn’t be more different. Oceanographers started out wanting to know if the ocean was keeping up with the amount of carbon dioxide people are putting into the atmosphere. Instead, they found that people aren’t the only players changing the ocean carbon cycle. Over decades, natural cycles in weather and ocean currents alter the rate at which the ocean soaks up and vents carbon dioxide. What’s more, scientists are beginning to find evidence that human-induced changes in the atmosphere also change the rate at which the ocean takes up carbon. In other words, it turns out that the world is not a simple place. More …

For eons, the world’s oceans have been sucking carbon dioxide out of the atmosphere and releasing it again in a steady inhale and exhale. The ocean takes up carbon dioxide through photosynthesis by plant-like organisms (phytoplankton), as well as by simple chemistry: carbon dioxide dissolves in water. It reacts with seawater, creating carbonic acid. Carbonic acid releases hydrogen ions, which combine with carbonate in seawater to form bicarbonate, a form of carbon that doesn’t escape the ocean easily.

As we burn fossil fuels and atmospheric carbon dioxide levels go up, the ocean absorbs more carbon dioxide to stay in balance. But this absorption has a price: these reactions lower the water’s pH, meaning it’s more acidic. And the ocean has its limits. As temperatures rise, carbon dioxide leaks out of the ocean like a glass of root beer going flat on a warm day. Carbonate gets used up and has to be re-stocked by upwelling of deeper waters, which are rich in carbonate dissolved from limestone and other rocks.

In the center of the ocean, wind-driven currents bring cool waters and fresh carbonate to the surface. The new water takes up yet more carbon to match the atmosphere, while the old water carries the carbon it has captured into the ocean.

The warmer the surface water becomes, the harder it is for winds to mix the surface layers with the deeper layers. The ocean settles into layers, or stratifies. Without an infusion of fresh carbonate-rich water from below, the surface water saturates with carbon dioxide. The stagnant water also supports fewer phytoplankton, and carbon dioxide uptake from photosynthesis slows. In short, stratification cuts down the amount of carbon the ocean can take up.

The rest of this feature article is available at: The Ocean’s Carbon Balance

Related Links:

• Southern Ocean already losing ability to absorb CO₂
• Oceans, Where Life Started, Are Dying - Part IV :  Researchers found evidence of corrosive water about 20 miles off the west coast of North America from Canada to Mexico.
• Human carbon emissions make oceans corrosive : ‘Carbon dioxide spewed by human activities has made ocean water so acidic that it is eating away at the shells and skeletons of starfish, coral, clams and other sea creatures …’
• The Eight Steps that Help Kill More of Our Fish : How Your Car’s Exhaust Emissions Helps Create Dead Zones and Kill Our Fish.
• Global warming could starve oceans of oxygen: study : Areas of the eastern Atlantic and Pacific Oceans with low amounts of dissolved oxygen have expanded in the past 50 years, apparently in line with rising temperatures.
• The Floating Toxic Garbage Island : A patch of garbage twice as large as the continental United States and dubbed the Great Pacific Garbage Patch floats in the middle of the Pacific Ocean in North Pacific Gyre.
• Oceans, Where Life Started, Are Dying - Part III : Tourism: The Most Destructive Human Activity After Warfare
• Oceans, Where Life Started, Are Dying - Part II : Major Problems: Fertilizer Runoff; Tourism; Coastal Developments [and Ocean Warming due to climate change]
• Oceans, Where Life Started, Are Dying - Part I : Our Oceans Are Now Dying!

Tipping Point: Here and Now!

Our thanks to Lisa G. for forwarding the link to the following (Source)

We are at the tipping point because the climate state includes large, ready positive feedbacks provided by the Arctic sea ice, the West Antarctic ice sheet, and much of Greenland’s ice. — James Hansen

Tipping Point: PERSPECTIVE OF A CLIMATOLOGIST [PDF]
by JAMES HANSEN

An Excerpt from Hansen’s report:
Our home planet is dangerously near a tipping point at which human-made greenhouse gases reach a level where major climate changes can proceed mostly under their own momentum. Warming will shift climatic zones by intensifying the hydrologic cycle, affecting freshwater availability and human health.

[James Hansen is director of the National Aeronautics and Space Administration Goddard Institute for Space Studies and an Adjunct Professor of Earth and Environmental Sciences at Columbia University’s Earth Institute.]

The ice in the Arctic is much younger than normal, with vast regions now covered by first-year ice and much less area covered by multiyear ice. Left: February distribution of ice by its age during normal Arctic conditions (1985-2000 average). Right: February 2008 Arctic ice age distribution. Credit: NSIDC [Caption: NASA]

Related Links:

• Arctic sea ice forecast:another record low in 2008
• Arctic Melting FAST!
• Greenland Ice Melt Faster Than IPCC Estimates
• Only Zero Emissions Would Avert Dangerous Warming
• Stern Report: “a great toxic dump of doublespeak in truly Orwellian fashion”

• Burning Earth
• Human Impact
• The First Wave of World’s Collapsing Cities
• Giga Trends
• Nuking Earth for Lifestyle

.-.

Repeat After Me!

WASHINGTON (AFP) — “A small group of US experts stubbornly insist that, contrary to what the vast majority of their colleagues believe, humans may not be responsible for the warming of the planet Earth.

“These experts believe that global warming is a natural phenomenon, and they point to reams of data they say support their assertions.”

There’s no such thing as global warming!

• Global Warming is a figment of our imagination [AAR, is has nothing to do with human activity. ]

• It makes no difference whether you have 290, 450, or 560 ppm (parts per million) of CO2 in the atmosphere. A million is a 1 followed by six zeros, you know how big a number that is? [AAR, what is to do with you, are you a f**king scientist or something?]

• There’s NO toxic pollution in the environment. Do you know how toxic dioxins, mercury … blah, blah are? They are so toxic even a minute trace of them in your breast milk could cause permanent brain damage to your baby. [AAR, it has nothing to do with industrial production.]

• There’s NO ozone hole in the atmosphere [AAR, the NASA conjurers could easily make anything disappear. ;-)]

• Our oceans are so clean and teeming with fish, you could eat from them. [AAR, they were OK just a few years ago; ask your grandma, she would tell you!]

• There’s no global shortage of potable water [AAR, what’s wrong with buying your own bottled water like the rest of us?]

• If fertilizers are good for the crops and vegetables, then sewage discharge into the rivers and coastal waters must be good for the fish. [AAR, just because you don’t eat fish, it doesn’t mean they should be starved!]

• There is no deforestation [or habitat what?] anywhere on the planet. [AAR, if we don’t cut all the trees they catch fire and pollute the air- heard about global warming, buster?]

• Land degradation is scientific mumbojumbo. [AAR, the same scientists have calculated that our planet can easily feed 14 billion people and produce enough ethanol to run 2 billion cars. How could it do all of that, if it were running out of cropland?]

Now close your eyes, take a big breath of fresh air and repeat after me…

Related Links: