Tag Archives: carbon

Our impact on the Earth

Here’s an impressive and rather scary visual of our impact on the earth, via the World Economic Forum.

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“We must. We can. We did!” Historic Paris Climate Agreement adopted

A historic agreement to tackle climate change and pave the way towards a low carbon, greener and cleaner future has been adopted by 195 nations in Paris.

This was a truly monumental political achievement that was only possible because of the deep urge felt unanimously by all member nations to act on one of the greatest challenges humanity has ever faced; that the climate is changing with disastrous consequences for people all over the world.

The Paris Agreement’s main aim is to limit global warming to well below 2 degrees Celsius by the end of the century and to drive efforts to limit temperature increase to 1.5 degrees.

The 1.5 degree Celsius limit is a significantly safer defence line against the worst impacts of a changing climate.

To reach these ambitious goals will require collaboration in a global scale, with richer nations providing much of the financial and technological means to implement low carbon, green initiatives throughout the world.

French President Francois Hollande told the assembled delegates: “You’ve done it, reached an ambitious agreement, a binding agreement, a universal agreement. Never will I be able to express more gratitude to a conference. You can be proud to stand before your children and grandchildren.”

Over the next few weeks I will be posting about the key implications of this agreement.

 

Details of the Paris Agreement can be found:
[1] http://unfccc.int/meetings/paris_nov_2015/in-session/items/9320.php
[2] http://newsroom.unfccc.int/unfccc-newsroom/finale-cop21

China’s carbon emissions may have been overestimated

An analysis of two major sources of China’s carbon dioxide emissions suggests that the country’s carbon emissions may have been overestimated in recent years.

China’s carbon emissions from burning fossil fuels and cement production are significantly lower than previous estimates. About 14% less in 2013 compared to estimates by the Chinese government and others according to research published in Nature this week.

About three quarters of the growth in carbon emissions from the burning of fossil fuels and cement production between 2000 and 2012 occurred in China. These helped to sate China’s booming energy thirst and boost its economy from around US $3,500 GDP per Capita in 2000 to over $8,000 in 2012.

A Chinese coal power plant. Source: WC/Tobias Brox
A Chinese coal power plant. Source: WC/Tobias Brox

The actual amount of carbon dioxide emissions from two major sources: burning fossil fuel and cement production has been plagued with uncertainties. The new study led by Zhu Liu from Harvard University re-evaluates data from 4,200 Chinese mines and incorporates new measurements of the emission factor of coal.

The team found that China’s carbon emissions from these two sources have been consistently overestimated.

“At the beginning of the project we thought that the emissions might be higher” than existing estimates, says Zhu Liu. “We were very surprised.”

Despite these new revisions to carbon emissions China is still the world’s largest emitter of carbon dioxide. Even when the lower estimates are taken into account, China’s carbon emissions for 2013 was still more than two-thirds higher than the second largest emitter, the United States.

Nevertheless, the new estimates represent a substantial decrease in annual global carbon emissions in 2013 by 0.35 GtC (billion tons of Carbon), an amount larger than the reported increase in global emissions between 2012 and 2013.

More information:
[1] Read the full paper here: http://www.nature.com/nature/journal/v524/n7565/full/nature14677.html
[2] http://www.nature.com/news/china-s-carbon-emissions-overestimated-1.18199
[3] http://www.nature.com/news/2007/070618/full/news070618-9.html

The Silk Road helped form a hidden carbon sink under the desert

Scientists have found a potentially large carbon sink in the most unlikely place on Earth – under the desert. The increase in carbon storage is linked with the rise of farming in arid landscapes.

This surprising conclusion comes from work done in the Tarim Basin of western China by Chinese and American scientists. The results are published in the journal Geophysical Research Letters.

“Basically, people thought the whole arid region is totally negligible to the global carbon budget,” says lead author Yan Li of the Chinese Academy of Sciences in Urumqi. “We are arguing that that’s not the case.”

Li and colleagues measured and dated the carbon content of water samples taken from a salty aquifer beneath the Tarim Basin. They show that the rate at which carbon sunk into the aquifer rose dramatically with the rise of farming and agriculture in the region. Rate of carbon storage increased by more than 12 times previous levels over the past 8000 years with particularly high levels beginning around 2000 years ago when the Silk Road opened.

How it works

The process began when humans started to grow crops on sandy soil. As the plants take in carbon dioxide from the air, some is released into the sand. Farming in desert conditions requires a lot of water to combat rising salinity caused by rapidly evaporating water. This organic carbon dissolves in the water and is transported down through the sand into deed salty aquifers.

Li_etal_2015
A schematic diagram showing the leaching and transport of DIC (dissolved inorganic carbon) in a closed arid basin. Source: Li et al, 2015

Normally these aquifers are tapped by rivers and streams and so the carbon comes back out of storage. But in the Tarim Basin the aquifer is a closed system, meaning that water does not escape, effectively locking away the carbon.

Li expects this process to occur in deserts around the globe but the amount of carbon would vary depending on the pH of the soil and the level of farming activity.

The results from this study will have important implications for the study of the global carbon cycle as desert regions were previously thought to be unimportant for carbon storage.

Read the full study here: http://onlinelibrary.wiley.com/doi/10.1002/2015GL064222/abstract