Deforestation And Wetland Loss Drive Global Warming Forward

DRAWDOWN — 100 Ways to Reverse Global Warming

“Drawdown” is a project-style book led by an American writer with contributions from researchers around the world. It presents what can be done to achieve “drawdown” — the point at which carbon dioxide levels begin to decline — organized broadly into two parts: an overview of what is already being done, and an introduction to future technologies. The “understanding of the current state” section in particular struck me hard, since there were many items whose details I didn’t know, or hadn’t even recognized. It deserves to be called required reading for working adults. At over 400 pages in two-column format, though, its actual volume is easily equivalent to three ordinary books, and even for me, a fairly fast reader, it took more than a month to finish.

So I want to extract and organize the essence of it to some degree. In any case, this is a book perfectly suited to grasping the big picture.

Here I’ll cover nature conservation.

The process of desertification

• Settlement and farming begin
• Forests are cut down to make fields and to obtain fuel
• Rain washes away nutrients from the soil, and irrigation causes salt damage
• The land dries out
• Overgrazing strips away the soil
• Desertification occurs

The same thing is happening in Syria, South Sudan, Libya, Yemen, Nigeria, Somalia, Rwanda, Pakistan, Nepal, the Philippines, Haiti, and Afghanistan. Myanmar, Thailand, India, Borneo, Sumatra, the Philippines, Somalia, Kenya, Madagascar, and Saudi Arabia have each lost 90% of their forests.

A brown river in Malaysia shows soil flowing down from logging upstream.

Germany leads in forest conservation technology and Norway leads in funding, and together they are trying to improve the situation in Brazil.

Wetlands

Coastal wetlands can store five times as much carbon as tropical rainforests, mainly in the deep layers. Marine plants die easily in low-oxygen conditions, and once dead they pile up quickly and decompose slowly under anaerobic conditions, trapping carbon underground. This is called blue carbon. Once dismissed as “useless land,” these areas have been developed heavily in recent decades, and a third of mangroves have been lost as a result.

A recent problem is that wetlands would normally shift as sea levels rise and fall, but roads now prevent that. In other words, the more sea levels rise, the more wetlands — prime carbon storage sites — are lost.

European companies have even planted mangroves in Senegal to earn carbon credits.

Peat

A state intermediate between solid and water. It is material that has decomposed slowly over hundreds of years under anaerobic conditions. Its carbon content exceeds 50%, and in the 17th century dried peat was a major fossil fuel. Peatlands account for only 3% of land area but store twice as much carbon as forests.

They need plants that absorb carbon and anaerobic conditions (water) that keep carbon from returning to the atmosphere. In short, marshes and swamps. They are found in the temperate-to-cold-climate zones of the Northern Hemisphere, in North America, Northern Europe, and Russia. 17% of Ireland is peatland. They also exist in tropical and subtropical regions such as Indonesia and Malaysia. Destruction in Southeast Asia is severe.

Peatlands emit methane, but their sequestration capacity is so strong that the net balance is said to be positive.

Trees’ sense of community

A tree stump cannot photosynthesize, so it is destined to die. But if there are trees nearby, their roots can overlap, and fungal threads can connect them, transferring nutrients between them. Plants can distinguish their own roots from others’ roots. Yet they deliberately pass nutrients to others. They know that without symbiosis a forest cannot form, and without a forest, a single tree cannot store water or withstand wind and rain.

Slash-and-burn agriculture

Many areas of the Amazon still use slash-and-burn methods. This creates a thin, acidic soil that temporarily raises yields but quickly degrades and becomes unusable. Native American controlled burns are also said to help prevent large-scale wildfires.

Bamboo forests

Bamboo stores more carbon than any other plant, grows easily even in poor soil, and grows faster than anything else. It is a highly promising plant, as strong under compression as concrete and as strong under tension as steel. But precisely because of that strength, it is disliked as an invasive species. It works best on degraded land, abandoned land, and land with steep slopes or heavy erosion.

The canopy only spreads as far as the point where it touches the branches of the neighboring tree.

Miyawaki-method afforestation

Many native species are planted on degraded land. Natural selection produces a resilient forest. After about two years of involvement, the rest can be left to nature.

Afforest

A project by entrepreneur Shubhendu Sharma. Open-source development for realizing a forest ecosystem on a small plot of land.

[New technologies and new attempts]

Ocean permaculture

The idea of planting forests in the ocean. Brian von Herzen holds a PhD in physics from Caltech. He built a career in Silicon Valley in electrical design and systems development before making the switch.

Kelp (large seaweed) supports many forms of life, much like a forest. Through photosynthesis it sequesters carbon dioxide and releases oxygen. It absorbs half of the carbon dioxide on Earth and produces half of its oxygen. Marine biological activity in the Atlantic is declining at an annual rate of 4-8%, exceeding what global warming models predicted.

Sinking arrays of kelp 25 meters below the sea surface sequesters carbon in the ocean. To begin with, the ocean stores 55 times as much carbon as the atmosphere. Even if all the carbon dioxide in the atmosphere were sequestered in the ocean, it would only raise the ocean’s carbon level by 2%. Anthropogenic carbon dioxide exists in the euphotic zone (down to about 150m depth). Kelp that absorbs it builds a food chain, and when it dies it sinks to the seafloor, carrying the carbon down with it. Phytoplankton, too, sink to the seafloor when they die, still holding their stored carbon.

When the sea surface heats up, vertical mixing weakens and the food chain breaks. To address this, pumps driven by lift and wave height bring cold water up from the seafloor.

When seaweed and kelp absorb nutrients, phytoplankton increase, and algae increase. Then herbivorous fish, crustaceans, and sea urchins increase. Carnivorous fish then increase to eat them, and seals, sea lions, and sea otters come to eat those. Seabirds and sharks follow, and finally fishermen increase. The result is a rich sea.

There is also an effort in New York’s Bronx River to improve water quality by growing kelp and shellfish.

Symbiosis among plants

Clements viewed forests as mutual aid systems, while Gleason viewed them as arenas of survival competition. Clements’s theory dominated in the first half of the twentieth century, but after 1947, in a United States entering the Cold War, even plant ecology was not permitted to speak of anything “communal,” so research came to be dominated by Gleason’s view.

In recent years — now that the fight against communism has ended and the idea of community feels entirely ordinary again — research on symbiosis has finally been able to advance, something that has taken nearly twenty years.

Callaway discovered that there are more nutrients under oak trees than in open grassland, and called this a chaperone effect.

There is also a phenomenon in the Amazon called “lift,” in which the primary root system carries rainy-season water deep underground, then in the dry season draws that water back up and distributes it to the surroundings.

Yareta: a plant that can live to be 3,000 years old. In the mountains of Chile, where ultraviolet light is strong and the climate is cold and dry, it forms mounds that serve as a base for raising many flowering species.

Wood Wide Web: the term for the underground connections among fungi. Fungi handle the exchange of nutrients, the exchange of information, and the distribution of carbon isotopes. On farmland, tilling the soil, spraying herbicides, and applying artificial fertilizer essentially tells those fungi, “You’re not needed.” As a result, the Wood Wide Web is never found on farmland, even though 80% of rooted plants normally host fungi.

The mammoth steppe

Before 11,700 BC, the Eurasian continent and the North American continent were connected. This was an ecosystem centered on the woolly mammoth. The conventional view holds that it went extinct due to rising temperatures, but researcher Sergey Zimov takes the opposite view.

His hypothesis: hunting reduced herbivore populations, and mammoths declined sharply as well. As grass decreased, the ground surface stopped being cooled, triggering a positive feedback loop.

To begin with, when herbivores in the Arctic clear away snow, the exposed turf actually cools the ground by 1.7-2.2°C. Many organisms once lived in the Arctic as well. When permafrost melts, they are exposed, releasing carbon dioxide and methane.

An attempt is underway to prove this hypothesis by creating Pleistocene Park in the Kolyma River basin in Siberia. Since mammoths no longer exist, Yakutian horses, bison, reindeer, and muskoxen graze there instead, and tanks knock down larch trees in place of mammoths, allowing brome grass (a type of grass) to grow.

[Related links] ・Notes on Drawdown (energy sector) ・Notes on Drawdown (agriculture sector)

Originally published in Japanese at https://clazytech.com/2021/12/818/. Translated with LLM assistance and reviewed before publication.