CO2 dominates Earth’s climate, NASA reveals

A new atmosphere-ocean climate modeling study shows that atmospheric carbon dioxide acts as a thermostat in regulating the temperature of Earth. Credit: NASA GISS/ Lilly Del Valle

A new atmosphere-ocean climate modeling study shows that atmospheric carbon dioxide acts as a thermostat in regulating the temperature of Earth. Credit: NASA GISS/ Lilly Del Valle

Almost 200 years after the greenhouse effect was discovered, and 150 years after its experimental proof, NASA scientists have finally demonstrated that CO2 is the most important greenhouse gas. That’s despite the fact that it only accounts for around one-fifth of the Earth’s greenhouse effect, whereas water vapour accounts for about half, and clouds – water in its solid or liquid forms – contribute a quarter.

“It often is stated that water vapour is the chief greenhouse gas (GHG) in the atmosphere,” write NASA’s Andrew Lacis, Gavin Schmidt, David Rind and Reto Ruedy in top journal Science on Thursday. “This would imply that changes in atmospheric CO2 are not important influences on the natural greenhouse capacity of Earth, and that the continuing increase in CO2 due to human activity is therefore not relevant to climate change. This misunderstanding is resolved through simple examination of the terrestrial greenhouse.”

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Saturday round-up: Cutting emissions, teacup by teacup

Heavily CO2 emitting coal-fired power stations like these are likely to supply the electricity to use to boil your kettle. And like your kettle, those power stations produce steam, which are the clouds shown here, not CO2 or smoke. Credit: Imperial College.

Heavily CO2 emitting coal-fired power stations like these are likely to supply the electricity to boil your kettle. And like your kettle, those power stations produce steam, which are the clouds shown here, not CO2 or smoke. Credit: Imperial College.

Your kettle and the milk you put in your hot drink are actually both powerful weapons with which to slash greenhouse gas emissions, research has underlined this week. For example, the energy the kettle uses could produce up to 60% more greenhouse gas emissions than governments have been assuming, claims Imperial College’s Adam Hawkes. “This means any reduction we make in our electricity use could have a bigger impact on the amount of carbon dioxide emitted by power stations than previously thought,” Hawkes explained. “However, this also acts in reverse: a small increase in the amount of electricity we use could mean a larger increase in emissions than we previously thought, so we need to make sure we do everything we can to reduce our electricity use.”

Hawkes studied emissions in the UK from 2002 to 2009, where the government estimates that CO2 emissions are 0.43 kilograms per kilowatt hour. That figure comes from averaging the amount of emissions produced by each different type of power source, a method commonly adopted across the world. However this ignores the fact that in the UK sudden changes in electricity demand are mainly met by coal-fired power stations, which produce lots of CO2. “A change in demand does not act upon all elements of the electricity system proportionally,” Hawkes wrote in a paper published in the journal Energy Policy last Tuesday. Read the rest of this entry »

For the love of science, not money

More walrus cubs being separated from their mothers are one effect mentioned by Louis Cotispodi as showing the effect that climate change is having in the Arctic (Photo by Phil Alatalo, Woods Hole Oceanographic Institution)

Louis Codispoti mentions walrus cubs being separated from their mothers as one effect that climate change is having in the Arctic (Photo by Phil Alatalo, Woods Hole Oceanographic Institution)

“I have had three colleagues killed while conducting research, so I take umbrage when hard-working, relatively under-paid, scientists are accused by the robber-barons and political hacks of hyping climate change for money.” So says Louis Codispoti, a scientist researching chemical processes happening in the ocean at the University of Maryland’s Horn Point Laboratory. At nearly 70, Codispoti is retiring to ease budget pressures at his university, but retains the title of professor and is beginning to pay for his own research.

Yet even without extensive funds, on March 12 Codispoti’s insights into how gas emissions from the ocean can add to global warming were published in the prestigious journal Science. Codispoti’s understanding of how the sea’s emissions of one particular gas – nitrous oxide, an especially dangerous greenhouse gas – might increase in relation to human activity has developed over 25 years. In that time, he’s seen researchers build the case for people causing climate change, and believes that the conclusions are backed up by way the world has changed in recent decades. Read the rest of this entry »

Saturday round-up: Dead zones reach skywards

University of Maryland's Louis Codispoti, who predicts increased nitrous oxide emissions from the sea could worsen climate change

University of Maryland's Louis Codispoti, who predicts increased nitrous oxide emissions from the sea could worsen climate change

The sea’s production of a greenhouse gas, caused in part due to human effluent, could increase as the world warms up. The nitrous oxide emitted due to changes in ocean make-up could worsen climate change, according to Louis Codispoti of the University of Maryland.

In the atmosphere, nitrous oxide strongly retains heat that would otherwise be lost into space. How much is released from the sea depends upon how much oxygen microbes living there have access to. If a given body of water were to fall from its maximum oxygen concentration to 1% of that, its nitrous oxide output would be 20 times greater.

Currently, human activity is thought to be reducing the oxygen content of many areas of the ocean, creating “dead zones”, also known as hypoxic waters. Sewage and fertiliser run-off promotes excessive plant growth in these regions. When these plants die, they are fed upon by micro-organisms that consume oxygen dissolved in the ocean, making it hard for fish and other creatures to live there. Read the rest of this entry »