That (carbon) sinking feeling - November 18, 2009
The world’s carbon dioxide ‘sinks’ are not able to keep up with the amount of the greenhouse gas being produced, according to a paper published in Nature Geoscience.
Reviewing the recent literature Corinne Le Quéré, of the University of East Anglia, and colleagues report that between 1959 and 2008 43% of each year’s carbon dioxide emissions have remained in the atmosphere with the rest being absorbed by land and ocean sinks. However in the last 50 years they suggest that the fraction remaining in the atmosphere has increased from about 40% to 45%.
They also found that a 29% rise in carbon emissions between 2000 and 2008 can be attributed to a large extent to burning coal and the growth of the so-called ‘emerging economies’.
“The Earth’s carbon sinks are complex and there are some gaps in our understanding, particularly in our ability to link human-induced CO2 emissions to atmospheric CO2 concentrations on a year-to-year basis,” says Le Quéré (press release). “But, if we can reduce the uncertainty about the carbon sinks, our data could be used to verify the effectiveness of climate mitigations policies.”
Uncertainties in this area are huge. Another recent paper in Geophysical Research Letters suggested there has been no decline in the fraction absorbed by sinks.
The author of that paper, Wolfgang Knorr of the University of Bristol, says, “We are just at the very edge of being able to detect a trend in the airborne fraction. Our apparently conflicting results demonstrate what doing real science is like and just how difficult it is to accurately quantify such data.” (Press release.)
One thing the authors can apparently agree on: if global warming is going to be stopped emissions are going to have to be reduced drastically.
Comments
is there anyway nationaly that a person could help or support? is there any future comments reffering to societys faults to this issue.
Posted by: shanodin m. | November 19, 2009 05:33 PM
The people should be given a chance to react to the things happening in the society in oder to reduce the atmosphere CO2 concentration
Posted by: girishvarma | November 19, 2009 05:43 PM
The world’s deserts are the only terrestrial areas capable of taking up the melt water that would otherwise contribute to sea level rise. Irrigating the hot deserts permits photosynthesis that could sequester a net 6.2 gigatons of carbon annually.
The world landmass is 148 million km² of which 27.5 million km² is Antarctica and the Arctic where vegetation is essentially non existent. The landmass that supports vegetation is therefore 148 million km² - 27.5 million km² or 120.5 million km².
According to the carbon balance sheet compiled by the Soil Carbon Center of the Kansas State University this area removes 110 billion gigatons of carbon annually through the process of photosynthesis and returns 61-62 gigatons through organic matter oxidation/erosion for a net sequestration of about 48 gigatons.
The hot deserts cover 15.6 million km² of the Earth’s surface and have the potential to sequester (15.6/120.5)*48 gigatons or 6.2 gigatons of carbon annually.
The missing ingredient for desert photosynthesis is water, which is also the threat to inundate coastal regions as a consequence of sea level rise.
The driver for sea level rise is first thermal expansion due to warming oceans and second melt water from depleting icecaps.
One way to irrigate deserts is to capture and transport melt water and river runoff before it mixes with seawater.
Currently such transportation costs are prohibitive except in the case of deadheading oil tankers returning to home ports in the Middle East and North Africa. Current global oil tanker capacity is sufficient to transport about 1.62 billion tons of pure water to desert regions near their home ports which is about the same amount of water currently being produced by desalination plants in Saudi Arabia.
The currently most viable approach to getting water into a desert environment is desalination with current costs of about 1.5 KWh/m3 using Reverse Osmosis.
One viable way to generate this power is using Ocean Thermal Energy Conversion (OTEC) technology, which converts the heat that otherwise would cause thermal expansion of the oceans and sea level rise to electricity. One terawatt (TW) continuously produced by OTEC would maintain oceans at current temperatures and negate thermal expansion. This 1 TW could be used to produce 5840 km3 of water annually which is enough to cover the world’s hot deserts with .375 metres of water per year and considering Saudi irrigation uses about 1.5 metres of water a year, about a quarter of the deserts could be irrigated and a net 1.5 gigatons of carbon sequestered.
OTEC uses the temperature difference existing between deep ocean water, typically at 5oC and shallow ocean waters, typically about 15oC, but as high as 24oC in equatorial regions where the deserts are found, to run a heat engine.
The working fluid of the system is a low-boiling-point fluid that is vaporized by the warm water, with the vapour driving the heat engine, which in turn drives a dynamo to produce electrical energy. The cold water condenses the vapour in a condenser
Cold ocean water is nutrient-rich whereas the warm water has been likened to a wet desert. More than 40% of all fish caught comes from the 0.1% of the ocean where cold, nutrient-rich water upwells to the surface.
OTEC artificially upwells this nutrient-rich water providing both a sustaining habitat for edible biomass and a natural CO2 sink.
The proposed solution would accordingly address the global need for water, energy and protein at the same time as it mitigates the cause and principal effect of Climate Change.
Posted by: Jim Baird | November 19, 2009 06:21 PM