Tag Archives: carbon sequestration

How Forests Create Clouds and Cool the Earth

Tropical forests have a crucial role in cooling Earth’s surface by extracting carbon dioxide from the air. But only two-thirds of their cooling power comes from their ability to suck in CO2 and store it. The other one-third comes from their ability to create clouds, humidify the air and release cooling chemicals. This is a larger contribution than expected for these ‘biophysical effects’ says Bronson Griscom, a forest climate scientist.

The analysis, published in Frontiers in Forests and Global Change in March 2022, could enable scientists to improve their climate models, while helping governments to devise better conservation and climate strategies. The findings underscore growing concerns about rampant deforestation across the tropics. Scientists warn that one-third of the world’s tropical forests have been mown down in the past few centuries, and another one-third has been degraded by logging and development. This, when combined with climate change, could transform vast swathes of forest into grasslands

Trees in the tropics provide shade, but they also act as giant humidifiers by pulling water from the ground and emitting it from their leaves, which helps to cool the surrounding area in a way similar to sweating, Griscom says. “If you go into a forest, it immediately is a considerably cooler environment,” he says.

This transpiration, in turn, creates the right conditions for clouds, which like snow and ice in the Arctic, can reflect sunlight higher into the atmosphere and further cool the surroundings. Trees also release organic compounds — for example, pine-scented terpenes — that react with other chemicals in the atmosphere to sometimes create a net cooling effect… When they considered only the biophysical effects, the researchers found that the world’s forests collectively cool the surface of the planet by around 0.5 °C.

Threats to tropical rainforests are dangerous not only for the global climate, but also for communities that neighbour the forests, Lawrence says. She and her colleagues found that the cooling caused by biophysical effects was especially significant locally. Having a rainforest nearby can help to protect an area’s agriculture and cities from heatwaves, Lawrence says. “Every tenth of a degree matters in limiting extreme weather. And where you have forests, the extremes are minimized.”

Excerpts from Freda Kreier, Tropical forests have big climate benefits beyond carbon storage, Nature, 

Dumping Carbon in the Seabed

Oil companies have for decades made money by extracting carbon from the ground. Now they are trying to make money putting it back. Energy giants such as Exxon Mobil and Royal Dutch Shell are pushing carbon capture and storage (CCS)—where carbon is gathered and buried underground—as part of a drive to reduce both their own and their customers’ emissions. Executives say the service could become a new source of income when the industry is grappling with how to adapt to a lower-carbon economy.

Oil companies have long captured carbon from their operations, albeit mostly to produce more oil. Now they want to retool that skill as a service they can sell to heavy-polluting industries like cement and steel, burying their carbon in the ground indefinitely for a fee, rather than releasing it into the atmosphere. Yet critics question the environmental benefits and high cost of such projects.

In 2021, Shell, Total and Equinor launched a joint venture to store carbon in a rock formation thousands of feet beneath the seabed off the coast of Norway. The state-backed Northern Lights project is set to be the first time companies outside the oil industry will be able to pay to have their carbon gathered and stored. Most carbon-storage projects rely on government funding. Norway is covering about 80% of the $1.6 billion cost of the Northern Lights project, with the rest split equally between Shell, Equinor and Total.

Exxon has said it plans to form a new business unit to commercialize carbon capture and storage, forecasting it could become a $2 trillion market by 2040. Chevron has formed partnerships on storage projects, while BP is codeveloping storage projects in the U.K. and Australia. Oil executives’ sales pitch to carbon-intensive companies: We will provide your energy, then take back the carbon to minimize your footprint. Carbon capture and storage iss becoming a business rather than just a solution. 

The U.S. offers companies a tax credit of as much as $50 a metric ton of carbon captured, while the U.K., Norway and Australia have collectively committed billions of dollars of funding for carbon-capture projects. But There are  concerns about whether storage sites could leak carbon. In Europe, public resistance to land-based storage has led to the use of aquifers and depleted gas fields in the North Sea….In the Norway project, carbon will be transported by ship around the bottom of the country before being pumped offshore via a 68-mile pipeline and then injected into an aquifer under the seabed. BP is working on a similar concept for a project it will operate in northeast England, where carbon will be collected from a gas-power plant and various industrial sites, then stored under the North Sea. “We’ll capture the carbon, we’ll take it offshore, we’ll stuff it underground,” BP Chief Executive Bernard Looney recently said of the project. “Taking the carbon back is what I like to describe it as.”

Excerpts from Sarah McFarlane, Oil Giants Turn to Carbon Storage, Apr. 20, 2021

How Mining Waste Can Help us Deal with Climate Change

Every year, mining and industrial activity generates billions of tons of slurries, gravel, and other wastes that have a high pH.

These alkaline wastes, which sit either behind fragile dams or heaped in massive piles, present a threat to people and ecosystems. But these wastes could also help the world avert climate disaster. Reacting these wastes with carbon dioxide (CO2) from the air solidifies them and makes them easier to handle.

At the same time, carrying out this type of an operation on a global scale could trap between 310 million to 4 billion tons of CO2 annually, according to recent surveys. That could provide the world with a much needed means of lowering atmospheric CO2.

But there are major hurdles. Governments will need to offer incentives for mineralization on the massive scale needed to make a dent in atmospheric carbon. And engineers will need to figure out how to harness the wastes while preventing the release of heavy metals and radioactivity locked in the material…

If regulators verified mines and other alkaline waste producers as CO2 sequestration sites…incentives would skyrocket, companies could claim tax benefits, and industry might start to tackle climate change on the grand scale that’s necessary.

Excerpt from Robert F. Service, The Carbon Vault, Science, Sept. 4, 2020