Seven audacious ideas to reverse global warming

How do we solve a problem like climate change? In the new book Drawdown, a team of over 200 scholars, scientists, policymakers, business leaders, and activists propose 100 practical solutions.

Here, the project's senior writerKatharine Wilkinson reveals seven of the most audacious and surprising ideas proposed so far.

How do you make a building that improves the world? That’s the central question behind the Living Building Challenge (LBC), first issued in 2006 and now a program run bythe International Living Future Institute.

LBC’s holistic approach has seven categories—Place, Water, Energy, Health and Happiness, Materials, Equity, and Beauty—that together define what a living building is and does. Living buildings should grow food and use rainwater, for example, while integrating elements of the natural environment('biophilic design') and eschewing toxic, 'red-listed'materials.

When it comes to greenhouse gas emissions, living buildings make their greatest impact by producing more energy than they consume. More than 350 buildings are in various stages of LBC certification, showing us that our constructions can do more than simply be less bad:they can generate a net surplus of positives for people and planet.

Imagine an energy source accessible and affordable to all—and available almost anywhere on the planet. That is the aim of the artificial leaf project, founded by Daniel Nocera, a Harvard professor of energy science. The inspiration is obvious: leaves are masterful at harvesting the energy of the Sun through photosynthesis, converting it into energy-rich biomass and sequestering carbon in the process.

Last year, Nocera and fellow professor Pamela Silver announced a giant step towards the goal of inexpensive fuel made withsunshine, water, air… and bacteria. First, a solar-powered process breaks water (H₂O) into hydrogen and oxygen. Then, engineered bacteria consume the hydrogen, along with carbon dioxide, and synthesisealcohol fuel. With higher efficiency than natural photosynthesis, the artificial leaf may someday become a real source of energy.

Like the artificial leaf, direct air capture (DAC) takes its inspiration from photosynthesis—the capture and transformation of carbon dioxide into plant matter. DAC machines act like a two-in-one chemical sieve and sponge. As the air passes over a solid or liquid substance, thecarbon dioxide binds with chemicals that are selectively 'sticky',ineffective on other gases. Once those capture chemicals become fully saturated, molecules of carbon dioxide can be extracted in purified form.

DAC shows promise for sequestering the planet’s most abundant greenhouse gas. What’s more, captured carbon dioxide can find a wide range of uses—from enhancement for greenhouses to synthetic transportation fuels to plastic, cement, and carbon fibre—though most are still nascent technologies. If DAC developers prove the technology can be both energy-efficient and cost-effective, its future will be bright.

On 29 kilometres of highway located south of Atlanta, Georgia, an initiative called The Ray is working to morph a stretch of asphalt into a positive social and environmental force: the world’s first sustainable, 'smart'highway.

Electric vehicles and clean energy are focal points for The Ray: infrastructure for solar-powered car charging, a solar photovoltaic (PV) farm along the highway right-of-way, and even PV road surfaces. The aptly named Wattway, a French technology, is a road surface that will producesolar electricity while improving tyre grip and surface durability.

Modern motorways have seen little advancement in design since their inception. Given climate change and the arrival of electric and autonomous vehicles, they need a smarter way forward. The Ray and other pioneers may prove that this dated infrastructure can become clean, safe, and even elegant.

Read more about climate change:

• Can planting billions of trees help tackle climate change?
• Christiana Figueres on climate change: “Net zero carbon is our only option”
• Could geoengineering cause a climate war?

Can we move transport beyond planes, trains, and automobiles? Inventor and entrepreneur Elon Musk imagines that humans and freight will, before long, have the option to travel through low-pressure tubes by levitated pod. He calls that vision the Hyperloop.

The promise of the Hyperloop is two-fold: speed—up to 1200 kilometres per hour—and efficiency—trimming energy use by 90 to 95 per cent. Both are aided by eliminating the friction of wheels and resistance of air.

Musk has made the Hyperloop concept public, tapping competition as an accelerant for its development. To date, various entities have built prototypes, and successful test runs are now on the books. Ultimately, passengers could glide from Amsterdam to Paris or San Francisco to Los Angeles in roughly half an hour—for the cost of a bus ticket.

Plants need nitrogen to grow. Today, many farmers supplement their fields with synthetic nitrogen fertilisers. While crop yields may rise, producing such fertilisers is energy-intensive. Unused nitrogen also migrates into waterways, causing overgrowth of algae and marine 'dead zones', and into the air as the potent greenhouse gas nitrous oxide.

Enhancing the soil microbiome—the microbes that call the soil home—offers a better way of nourishingplants. In a thimble’s worth of soil, there can be up to 10 billion microbial denizens: bacteria, nematodes, fungi, and more. Legumes, such as alfalfa and peanuts, have a symbiotic relationship with select bacteria, passing carbon to them in exchange for nitrogen.

Most crops lack this ability, which is why scientists are looking to harness microbes that can work more broadly—with wheat, rice, and more. Someday, farmers may opt out of nitrogen fertilisers and use nitrogen-fixing bacteria instead.

Permafrost is a thick layer of perennially frozen, carbon-rich soil that covers a quarter of the Northern Hemisphere. Perma indicates permanence, but this soilis thawing as the world warms, releasing greenhouse gases in the process. Sergey and Nikita Zimov, father-and-son scientists, are piloting a solution in Siberia: returning native fauna to the area.

A grassland ecosystem called the mammoth steppe once spanned the regions where permafrost is found. Today, herbivores no longer roam the region, except at the Zimovs’ Pleistocene Park. When Yakutian horses, reindeer, musk oxenand the like push away snow and expose the turf underneath, the soil is no longer insulated and drops a couple of degrees in temperature—just enough to remain frozen.

Repopulating the mammoth steppe more broadly, the Zimovs say, could help to keepthe permafrost frozen, and the greenhouse gases locked up.

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