Struggles from below

According to scientists’ best estimates, the world needs to halve its greenhouse gas emissions before 2050 to avoid the most catastrophic repercussions of climate change. Of all the greenhouse gases, carbon dioxide is the most prevalent, primarily driven by humanity’s ever-growing appetite for fossil fuels. The situation has got so bad that, in order to hit our targets, not only do we need to stop releasing carbon, we also need to take some of it back.

Plants are the best candidate for the job. Through photosynthesis, they pull CO2 out of the atmosphere and store it in their roots, stems and leaves. Hence the global push to promote reforestation efforts in recent years. But trees aren’t the only answer.  

Grasslands—unlike their arboreal counterparts—store most of their carbon underground, in their roots and the soil. And that means they’re more reliable “carbon sinks” than forests, according to a 2018 study by the University of California, because the carbon isn’t released back into the atmosphere if the grasslands burn.

In our top story this week, by The Washington Post’s Mary Beth Gahan, we learnt about an initiative aiming to pay US landowners to preserve the country’s native prairies in order to sequester carbon from the atmosphere.

Jim Blackburn, an environmental lawyer and Rice University professor, and The Baker Institute at Rice are heading up a group of organisations—varying from the Nature Conservancy to Valero Energy—looking to create a market for storing carbon in the soil of the country’s prairies, farms, ranches and grasslands. Funding is available for landowners to store carbon in forests, as with California's cap-and-trade market, and the same should be the case for soil, say the advocates. The group is launching a nationwide programme to do just that: landowners sign up for a 10-year commitment; and if the land is sold, the commitment restarts. 

The US produced close to 7 billion metric tons of CO2 in 2018, according to the Environmental Protection Agency. An acre of pristine prairie can store up around 5 tons of carbon. And Blackburn estimates that all the country’s grasslands could capture around 1 billion metric tons of CO2 annually. 

Similar realisations are occurring elsewhere in the world, with conservationists turning to long disregarded native plant populations in a bid to capture the atmosphere’s excess carbon.

In South Africa, one initiative is trying to resuscitate a thicket of Spekboom succulents that was once the size of Cyprus and holds huge carbon-capturing potential. Because of the plant’s hardiness, one tonne of CO2 can be captured for less than a tenth of the cost of sinking the equivalent carbon by planting trees in temperate or tropical forests.

The UK’s Seagrass Ocean Rescue project is laying kilometres of rope embedded with millions of seeds off the Pembrokeshire coast in an attempt to restore the area’s decimated seagrass meadows. The meadows store carbon 35 times faster than tropical rainforests and harbour up to 40 times more marine life than seabeds without grass. 

And in Tasmania, researchers are looking to revive the island’s native kelp forests, steadily killed off by climate change since the 1960s, because of the seaweed’s huge potential to extract carbon out of the atmosphere and deposit it deep in the seabed.

As with the trees, none of these plants represent the only answer to our carbon conundrum. But collectively, they could go a long way to helping us reach our targets.