All posts by ekh351

I'm Ekbal. Highly enthusiastic, eternal optimist and passionate about science communication. I blog about the science and social impacts of climate and natural hazards.

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

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Will we lose our crops to climate change?

With the World’s population now past 7 billion and projected to increase to 9 billion by 2050, stress on the food production system is at an all time high. To make matters worse it appears that our crop yields may fall victim to the effects of climate change.

Crop yields to drop by 25 percent towards the second half of the century.
Crop yields to drop by 25 percent towards the second half of the century.

Global warming of only 2°C will be detrimental to the production of rice, wheat and maize in temperate and tropical regions, with reduced yields from the 2030s onwards claims a study, published in Nature Climate Change last year, led by the University of Leeds scientists.

“Climate change means a less predictable harvest, with different countries winning and losing in different years. The overall picture remains negative, and we are now starting to see how research can support adaptation by avoiding the worse impacts,” says lead author Professor Andy Challinor.

The study shows that we will see, on average, an increasingly negative impact of climate change on crop yields from the 2030s onwards. The impact will be greatest in the second half of the century, when decreases of over 25% will become increasingly common.

These statistics already account for minor adaptation techniques employed by farmers to mitigate the effects of climate change, such as small adjustments in crop variety and planting date.

The IPCC projected temperature increase for the next century.
The IPCC projected temperature increase for the next century.

The latest Inter-governmental Panel on Climate Change (IPCC) reports state that the expected temperature increase for the end of the century is somewhere between 1.5 and 4 degree Celsius. And thus, major agricultural transformations and innovations will be needed in order to safeguard crop yields for future generations.

Read the full study here: http://www.nature.com/nclimate/journal/v4/n4/full/nclimate2153.html

Climate change explained in 60 seconds

Climate science explained in 60 seconds by the Royal Society and the US National Academy of Sciences.

Review: Risk

Risk_Dan_Gardner“We live in an age of fear”, says Dan Gardner in the opening pages of Risk: The Science and Politics of Fear. Despite the fact that you are more likely to live for longer and healthier now than any other time in human history, we are constantly afraid for our lives.

Homo sapien has been around for over 50,000 years. For much of this time we were hunter gatherers. Those who learned to fear the unknown were the ones who lived the longest. Thus, this trait was passed on down the generations until it became ingrained into our cognitive anatomy.

But for the past 3 or 4 centuries we have not been of that world. Most of the world’s people do not need to hunt for their food. With more than half of the global population living in cities we have become Homo sapien urbanus. But 50,000 years of evolution is hard to forget. Our intuition, still hard wired as a hunter gather, has been thrown into the urban mayhem that is modern life.

It is therefore not surprising that our instinct gets things wrong.

Using clear and elegant prose Dan Gardner explains the results of decades of psychological research on why our rational, logical mind often loses out to irrational gut instinct. And how modern day politicians, journalists and marketers have exploited our instinctive misunderstanding of risk to forward their agendas, stories and products. The author echoes President Franklin Roosvelt who famously said that ” the only thing we have to fear is…fear itself”

Filled with illuminating real world examples and interviews with experts, Risk: The Science and Politics of Fear is an engaging and thought provoking read that will make you question the decisions you make.

I believe this book should be a staple for everyone interested in understanding the science and perceptions of risk.

Earthquake liquefaction causes ground to open and close

The 2011 magnitude 9 earthquake in Japan was one of the largest earthquakes ever measured. Strong shaking and the consequent tsunami caused the death of nearly 18,000 people.

Strong vibrations in earthquakes can cause soil particles in the ground to jiggle about and lose contact with each other. If there is a lot of water within the ground the shaking causes soil to behave more like a liquid than a solid. This process is called liquefaction.

Footage taken by an American tourist shows dynamic movements of the ground during the Japan earthquake. The changing pressures caused by the soil movement can force water out of the ground and form moving cracks on the surface.

Note that this is not ground movements caused by the actual shaking in the earthquake, but by secondary soil movements.

Sustainable development using earthquake resistant bamboo houses

By Dalmeet Singh Chawla

Governments should pay more attention to the role that bamboo and rattan can play in building more sustainable and greener economies, a pressure group has told a UN meeting.

“Bamboo and rattan are not always seen as tools to deliver on the Sustainable Development Goals. We believe they bring major opportunities,” the International Network for Bamboo and Rattan (INBAR), an intergovernmental group based in Beijing, China, told the UN Forum on Forests in New York, United States earlier this month.

“Modern bamboo houses are more flexible in an earthquake, as they flex and absorb some of the energy.”
Hans Friederich, International Network for Bamboo and Rattan

For example, bamboo can reduce soil erosion and restore degraded lands, and ultimately help protect the livelihoods of people who depend on forest ecosystems. Products derived from the two plants could also bring income to millions of people in developing countries, the group says.

INBAR, which has 40 member states, called on policymakers to include bamboo and rattan in their action plans for forest development.

Construction of a 100% bamboo house in Martinique, certified earthquake and cyclone resistant. Credit: J'ai pris cette photo
Construction of a 100% bamboo house in Martinique, certified earthquake and cyclone resistant.
Credit: J’ai pris cette photo

INBAR also presented the Global Assessment of Bamboo and Rattan, an initiative that aims to exchange knowledge and data about bamboo and rattan. The assessment is expected to be launched at the World Forestry Congress in Durban, South Africa, in September 2015.

Bamboo and rattan grow across much of the developing world, including in many equatorial countries in Asia, Africa, Latin America and the Caribbean. They make good alternatives to wood charcoal and cotton fibres, and bamboo can be burned or used in biogas systems to provide a sustainable source of bio-energy.

Bamboo can grow at a rate of up to one metre per day, and can be harvested for productive use after 3-7 years, compared with 10-15 years for conventional trees. Hence, using bamboo as a replacement for other wood would lead to fewer trees being cut down for processing, INBAR says.

“Because bamboo grows quickly it also absorbs carbon quickly, and is what we call a strategic forest resource in the battle against climate change,” says Hans Friederich, director general of INBAR.

But Ramadhani Achdiawan, a researcher from the Centre for International Forestry Research in Indonesia, underlines the importance of forest planning for the long term if countries want to use bamboo and rattan for economic growth. For instance, Achdiawan says that “rattan needs trees to support its growth, so maintaining big trees in forests is very important”.

In its statement, INBAR also told UN representatives about bamboo and rattan’s potential as construction materials to build strong houses and furniture that will withstand natural disasters.

“The recent terrible earthquake in Nepal has highlighted the need to build better for natural disasters,” Friederich says. “Modern bamboo houses are more flexible in an earthquake, as they flex and absorb some of the energy.”

This article was originally published on SciDev.Net. Read the original article.