Stories tagged carbon dioxide

In honor of American geologist Dr. Richard Alley's recent election as the Foreign Member of the Royal Society, the National Science Foundation has posted this series of 15 short videos explaining the science behind climate change and starring Dr. Alley.

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Prehistoric Antarctica shoreline: artist's conception of flora living during the Middle Miocene epoch.
Prehistoric Antarctica shoreline: artist's conception of flora living during the Middle Miocene epoch.Courtesy NASA / JPL-Caltech / Dr. Philip Bart, LSU
Recent investigations into microfossils show that Antarctica hasn’t been quite the icebox scientists have imagined it to be over the past 34 million years. Pollen and leaf wax samples from Miocene-aged sediments indicate the continent has experienced some periods of warming since the beginning of the most recent glacial period. The core samples studied came from ocean sediments collected near Antarctica, and particulates found in the samples indicate more rain fell on the ice-covered continent during the Middle Miocene epoch (15.5 – 20 million years ago) than previously thought, enough rain to spur the growth of forests of small, stunted trees.

Paleoclimatologist and organic geochemist Sarah Feakins of the University of Southern California and her colleagues analyzed core samples taken from between 144 and 1,100 meters beneath the ocean floor – levels dating back to the Middle Miocene. Spikes of concentrated amounts of pollens and leaf wax appeared in two periods – one about 16.4 million years ago, and another about 15.7 million years ago. The warm periods were relatively short, each lasting less than 30,000 years.

In a previous study, palynologist Sophie Warny of Louisiana State University had first described the pollen and leaf wax spikes found in the core samples, and she and Feakins eventually teamed up for the recent study. The team determined the particle spikes didn’t arise from the leaf wax and pollen blowing in from elsewhere but rather came from two species of trees that once lined the shores of Antarctica. The two species, podocarp conifer and southern beech wouldn’t have grown very tall – maybe knee-high – and neither spreads their pollen over wide areas. Had the pollens blown in from elsewhere - say South America or New Zealand - there were would have been more species in the mix.

Using a mass spectrometer, Feakins and NASA researchers analyzed the ratio of hydrogen to deuterium atoms in the wax molecules which indicated the temperature at the Antarctica location during the two warm periods was about 7 degrees Celsius during the summer. Today, summer temperatures in the same region are about –4 °C. The average global temperature at the time was about 3 °C higher than it is today. As the overall global temperature changes a relatively greater change in polar temperature isn't unexpected due to a process called polar amplification.

The data from Feakins and Warny’s study, which appeared in Nature Geoscience, adds to growing concerns over the sensitivity of Earth’s climatic and hydrological systems. At the moment, no trees line the shores of Antarctica, but current levels of carbon dioxide (393 parts per million) are not far off those thought to have existed during the Middle Miocene’s warm periods (400-600 parts per million) when forests did exist on the margins of the icy continent. This could indicate that even small changes in carbon dioxide levels can are capable of creating big changes in climate.

Earth magazine
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Carbon dioxide, you light up my life. Or you could, anyway, if this weirdo has his way. Said weirdo is biochemist Pierre Calleja, who has developed a light that can run on carbon dioxide rather than electricity. His secret: green algae that produce energy when they consume CO2.

The mucklight powerhouse: Gross.
The mucklight powerhouse: Gross.Courtesy Jim Conrad

One large lamp he installed in a parking garage consumes up to one ton of CO2 per year. While that's just a drop in the air--the US alone emits almost 5.5 thousand metric tons per year--just think how much these lamps could consume if we replaced all the streetlamps, parking ramp lights, and other environmental lamps with them. It sounds like a pretty great idea when you consider that CO2 is a major driver of global-scale changes in our climate. Whoda thunk we could tackle our warming climate by turning on the lights?


Cumulative impact by humans on the ocean
Cumulative impact by humans on the oceanCourtesy National Center for Ecological Analysis and Synthesis
One of the great extinctions in Earth history occurred 252 million years ago when about 95 percent of all marine species went extinct. The cause or causes of the Great Dying have long been a subject of much scientific interest.

Now careful analyses of fossils by scientists at Stanford and the University of California, Santa Crux offer evidence that marine animals throughout the ocean died from a combination of factors – a lack of dissolved oxygen, increased ocean acidity and higher water temperatures. What happened to so dramatically stress marine life everywhere?

Geochemical and fossil evidence points to a dramatic rise in the concentration of carbon dioxide in the atmosphere, which in caused a rapid warming of the planet and resulted in large amounts of carbon dioxide dissolving into the ocean and reacting with water to produce carbonic acid, increasing ocean acidity. The top candidate for all this carbon dioxide? – huge volcanic eruptions over thousands of years in what is now northern Russia.

Why should the Great Dying be of more than just academic interest? Humans currently release far more carbon dioxide into the atmosphere than volcanoes and we are releasing carbon dioxide into the atmosphere at a rate that greatly exceeds that believed to have occurred 252 million years ago. The future of Earth’s oceans will be determined by human decision making, either by default or by design. What do we want our future ocean to be?


Atmospheric carbon dioxide concentration during the past 417,000 years
Atmospheric carbon dioxide concentration during the past 417,000 yearsCourtesy Wikipedia Commons
Skeptics of human-induced climate change have long pointed to a lag between an increase in temperature and a rise in atmospheric carbon dioxide at the end of the last Ice Age as suggesting that carbon dioxide is an effect of rising temperatures, not a cause. This lag, however, was based on evidence from only one place on Earth - ice core records from Antarctica.

A much more extensive study of paleo-temperature records from 80 sites around the world just published in Nature reveals that global temperature increases followed rises in the carbon dioxide concentration in the atmosphere. Carbon dioxide is a heat-trapping gas that can drive climate change. This study greatly substantiates climate scientists who point out that the enormous quantities of carbon dioxide that human activities are putting into the atmosphere will result in dramatic changes in global climate if they are not curtailed.


Red cabbage juice is a safe, natural, easy-to-make acid/base indicator that allows you to see the carbon dioxide in your breath. The trick is to use a very small volume of cabbage juice, since it's not very sensitive.
CO2 red cabbage experiment
CO2 red cabbage experimentCourtesy Liz Heinecke

You'll need red cabbage, drinking straws, and very small cups (sample cups or the ones for measuring liquid medicine with work well.) Chop a head of red cabbage, cover it with water in a pan, and boil for about 10 minutes. Then, let it cool and collect the juice. The juice will be purple, but it turns blue when exposed to a base or pink when exposed to an acid. Pigments in the cabbage, called flavanoids, change color when they come in contact with acids and bases.

Pour an equal volume- a teaspoon or two (5 to 10 ml)- of the (cooled) juice into each of two small cups. Take a straw, put it all the way against the bottom of one cup and blow through the straw repeatedly for a few minutes until you see the cabbage juice you're blowing into turn noticeably pinker than the juice in the control cup.
red cabbage CO2 test photo 2
red cabbage CO2 test photo 2Courtesy Liz Heinecke

What happens? The carbon dioxide in your breath combines with the water in the cabbage juice to form carbonic acid, which causes the pH of the solution to drop, making the pigment in the cabbage juice turn pink.

Why is this interesting? About a quarter of the carbon dioxide released by activities like burning fossil fuels and burning down rainforests is absorbed by our world's oceans. This results in the ocean water becoming more acidic, like the cabbage juice in the experiment, and can have an effect on sea life, like coral. To learn more about ocean acidification and the chemistry of ocean acidification, check out NOAA's amazing website.

If you have some cabbage juice left over, you can soak white coffee filters in it, dry them and cut them into strips to make litmus paper. It's also fun to pour 1/4 cup of cabbage juice into each of two cups, add a Tbs. baking soda to one cup, 2 Tbs. of vinegar to the other cup and then pour one cup into the other to see lots of carbon dioxide bubbles form as the vinegar (acetic acid) reacts with the baking soda solution (sodium bicarbonate.)


What do a banana and a chunk of coal have in common? Carbon!

Dr. Peter Griffith, Director of NASA's Carbon Cycle and Ecosystems office, spoke to twenty of us training to be Earth Ambassadors for NASA about why it's important to teach people about the way carbon moves around on our planet, in order to help them understand climate change.

He showed us this fantastic video that describes the Carbon Cycle on earth and describes how "young, fast carbon" like that in a banana differs from "old, slow" carbon, like that in coal and other fossil fuels.

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Dr. Griffith also described how you can tell the difference between objects containing old carbon and young carbon by looking at the radioactive decay of carbon 14. Carbon in its normal state is called carbon 12, or C12. However, cosmic rays, like those from the sun, convert some atmospheric carbon into a slightly radioactive form called carbon 14, or C14. Over time, this carbon decays back into Carbon 12.

All living plants and animals contain some C14, since they constantly take in atmospheric carbon dioxide.

Fossil fuels like coal and oil, which have been underground for millions of years, contain only C12 (fully decayed Carbon,) while a banana still contains some C14 from atmospheric carbon dioxide the banana tree absorbed.

It is not surprising that the carbon downwind of power plants burning coal is mostly C12. Trees can also lock up carbon in their trunks and branches in for many years.

The carbon released by burning fossil fuels and setting tropical forests ablaze is carbon that would naturally have remained "locked" up. Human activities like these are creating an excess of long-lived carbon dioxide gas in the atmosphere and are causing our world's climate to warm.

NASA and other scientists are working hard to study the science of climate change. How our planet and its inhabitants will respond to the challenges resulting from this change remains to be seen.

The idea of a synthetic tree to capture excess carbon dioxide from the air was announced in 2003. After years of work, physicist Klaus Lackner will present a public demonstration of the technology today (October 26, 2011) at the London headquarters of the Institution of Mechanical Engineers. Artistic Representation of a Synthetic "Tree Farm"
Artistic Representation of a Synthetic "Tree Farm"Courtesy Institution of Mechanical Engineers

The prototype tree, which looks like a goal post with Venetian blinds, draws carbon dioxide (CO2) out of the air like a plant, but unlike a plant, retains the carbon and does not release oxygen.

Klaus Lackner estimates that some 250,000 such trees, which potentially could be planted anywhere*, even in desert regions, would be needed to soak up the CO2 produced by human activity annually.

Live Webinar at 12:00pm Central Daylight Time, October 26, 2011 (duration 3 hours): Artificial Trees: Giving us the time to act?
Columbia University blogpsot: Artificial Trees: Giving Us Time to Act?

* Well, not anywhere, as I later found out from the Environment 360 blog; the tecnology won't work in cold boreal regions or the humid tropics. And regarding the use of organic trees for carbon capture, see Chapter 31 of David McKay's Sustainable Energy - Without the Hot Air.


You probably know that plants "inhale" carbon dioxide and "exhale" oxygen, but did you know that plants also release water into the air when they exhale? This process is called transpiration, and it plays an important part in our planet's water cycle. I mean, just think of all the billions of plants out there, all of them transpiring 24/7--that really adds up.

Unfortunately, increasing carbon dioxide in the atmosphere has yet another impact on our ecosystems--it reduces transpiration. You see, plants have these tiny pores on the undersides of their leaves called stomata. The stomata open and close depending on the amount of carbon dioxide available in the air and how much they need of it.

It's kind of like your eye's iris--your eye needs an ideal amount of light to see, so when it's bright outside, the iris closes in. This shrinks the pupil so that it only takes in a small amount of light. In lower light, the iris opens, making the pupil larger so that it takes in more light. Like your iris, the stomata open and close to let in the right amount of carbon dioxide.

Stomata: These stomata are from an Arabidopsis plant. The top one is open, and the lower one is closed.
Stomata: These stomata are from an Arabidopsis plant. The top one is open, and the lower one is closed.Courtesy KuriPop

Unfortunately, a recent study showed that with carbon dioxide concentrations increasing quickly, plant stomata are closed longer than they were 150 years ago. There are also simply fewer stomata in leaves. While this controls the amount of carbon dioxide they're absorbing, it has the added outcome of limiting the amount of water released into the air from plants. Over time, this could add up to some significant change--but it's a little early to tell for sure what the impacts will be.

It's kind of amazing to see how changes in carbon dioxide emissions have such far-reaching impacts beyond the one we hear about every day--global warming. Luckily, we have plenty of ways to work on global warming and curtail carbon dioxide emissions, such as cement that absorbs carbon dioxide as it hardens, castles that scrub CO2 from the air, and solar power concentrators that generate 1500 times as much energy as regular solar cells, reducing our dependence on fossil fuels.

What's your favorite way to ditch carbon dioxide?