When we talk about combating climate, the most obvious issues that come to mind are policies to prevent carbon dioxide emissions — cap-and-trade programs and carbon taxes and environmental regulations. Then there are the technological solutions like renewable energy and electrified vehicle fleets and more energy efficient infrastructure. If people are feeling desperate, they start discussing geoengineering
But one part of the climate change solution mix doesn’t get talked about as often, perhaps because it’s almost too obvious: we need more plants. Or, more specifically, we need more forests.
Thanks to photosynthesis — the process by which plants convert sunlight into energy — trees and other flora remove carbon dioxide from the atmosphere and release oxygen. This allows them to act as a “carbon sink” — any process that results in a net removal of carbon from the atmosphere. Conversely, deforestation releases the carbon forests store up back into the atmosphere. The 2007 report from the United Nations’ Intergovernmental Panel on Climate Change determined that deforestation contributes roughly 17 percent of all greenhouse gas emissions, putting it in third place behind the global energy sector’s 26 percent and the global industrial sector’s 19 percent. Most of that action is in tropical forests, where the most egregious deforestation is occurring. Also, contrary to the image of individual rural farmers chopping down rainforest for crop land, most tropical deforestation these days can be laid at the feet of major industries and corporations.
What It Can’t Achieve
Start with the bad news. A recent article in The Conversation pointed to a 2011 study that attempted to measure the effect of living biomass, dead wood, and other organic products from temperate, boreal, and tropical forests between 1990 and 2007. Assessing global satellite data, global forest growth, and density is tough, but the researchers determined that Earth’s forests are taking in around 4 billion metric tons of carbon a year. Unfortunately, deforestation — which exists in a constant tug-of-war with regrowth — rolled a lot of that back, resulting in a net carbon sink effect of 1.1 billion metric tons annually.
The problem is the sheer scale of the numbers surrounding the global forest carbon sink. In 2010, fossil fuel burning, cement production, land use — including deforestation — dumped a grand total of 36.7 billion metric tons into the atmosphere. But only half stayed there. (Deforestation’s 17 percent contribution was to that final atmospheric amount.) The rest was absorbed by the oceans and the land, the latter including the forest carbon sink’s 4 billion metric ton contribution.
Those numbers were about the same in 2011. So just considering the carbon dioxide that got into the atmosphere, even getting back all 3 billion metric tons lost to deforestation would take out only a slice of the problem. The most pessimistic study on this front was released in 2013, and determined that even the best case scenario of deforestation reduction would cut atmospheric concentrations of carbon dioxide by 40 to 70 parts per million (ppm). That’s in comparison to the up to 600 ppm above 2000 levels human activity is anticipated to add by 2100 under most projections.
There are lots of reasons why reforestation’s potential to curb climate change is limited.
Given human needs and activity, complete reforestation is obviously a pipe dream. Younger and recently planted forests also tend to take in less carbon than older and more developed forests, and carbon can remain in the atmosphere for thousands of years — making the path from fossil fuel reserves underground to burned emissions effectively a one-way ticket. Even without deforestation, a forest’s carbon intake for photosynthesis enters into a natural equilibrium with natural fires, decomposition, and other processes that return some of their carbon to the atmosphere under much shorter time periods. So the researchers concluded the most important reason to fight deforestation is to preserve the remaining forests not caught in the deforestation-regrowth tug-o-war, and which have held the most carbon the longest. Losing all of them would add another 130 to 290 ppm to atmospheric carbon concentrations.
That’s really the key take away: fighting deforestation won’t be able to help us roll climate change back that much, but it can help us hold the line against things becoming any worse. But there are other reasons to keep up the fight as well.
What It Can Achieve
Progress on preventing deforestation is mixed, but overall seems to be trending in the right direction. Brazil recently announced that rainforest deforestation there was reduced 84 percent over the last eight years, hitting 1,764 square miles from mid-2011 to mid-2012 — the lowest rate since the country began monitoring it. (Though there are concerns that failure by the Brazilian government to properly enforce its forestry code could reverse that trend.) At the same time, the Mekong region — which encompasses Vietnam, Thailand, Laos, Cambodia, and Myanmar — lost nearly a third of its forest cover between 1973 and 2009. Globally, we’ve seen carbon dioxide emissions from deforestation drop by over 25 percent since 2000, in comparison to 1990s levels.All that said, we can certainly do better on fighting deforestation. After assuming relatively high levels of economic and population growth a 2007 study, found that reducing present deforestation rates by 50 percent by 2050, and then holding the line until 2100, could prevent as much as 50 billion metric tons of carbon emissions this century. That’s 12 percent of what’s needed through 2100 to stabilize atmospheric concentrations of carbon at 450 parts per million — the threshold beyond which most scientists agree the threat of catastrophic climate change becomes intolerable. The IPCC estimates this could be done for less than $20 per ton.
There’s also ocean acidification to consider. Approximately 10 billion metric tons of the carbon dioxide that didn’t enter the atmosphere in 2011 was absorbed by the oceans, driving up the creation of carbonic acid and threatening a whole host of marine ecosystems.
Human jobs and human lives sit at the top of many of those food chains; about one billion people around the world rely on seafood as their primary source of protein, the vast majority of them in poor and under-developed countries. So every bit of carbon taken in by forests is carbon that isn’t threatening ocean life.
Finally, there’s a feedback loop to keep in mind. Preventing tropical deforestation slows down the climate change that leads to more deforestation, and vice versa. In the rainforest specifically, trees and vegetation actually introduce additional moisture into the air, meaning deforestation reduces rainfall. That makes hydroelectric power harder to produce: a study warned that this process could eliminate 40 percent of the power produced by Brazil’s Belo Monte hydropower complex — the third biggest in the world — which is a problem for a country that gets 80 percent of its electricity from hydropower.
What We Can Do About It
An international mechanism to financially reimburse countries for preventing deforestation has been in the works at the United Nations for several years now. Called REDD or REDD+ (Reducing Emissions from Deforestation and Forest Degradation) it’s already provided $67.3 million in 16 partner countries. Unfortunately, the program wasn’t part of the Kyoto negotiations in 1997 (though it may make its way into the Paris talks in 2015) and only has $112.5 million to work with, thanks to donations from Norway, Denmark, and Spain. Japan and the European Commission have pledged funds as well, but so far the United States has not contributed a cent. And many of the details for how REDD should operate remain in dispute. So a serious move by the United States’ government to both bulk of REDD’s funding and push it along policy-wise could certainly help.
Granted, REDD is not without its critics or possible pitfalls, particular the fact that much of the program — so far as its developed — is structured around offsets. Monitoring and verifying offsets, which allow one actor to continue emitting a certain amount of carbon if they pay some other actor to carry some net carbon negative act, can be logistically and conceptually difficult. And of course, offsets still allow emissions elsewhere. A better approach for REDD might be to financially encourage developing countries to preserve forests, with no counterbalancing allowances for carbon emissions elsewhere. Just straight up pay them to conserve, on the precept that economically underprivileged countries should not be bearing the burdens of climate change.
Climate Advisors and other groups have also just put forward a raft of recommendations for other ways the United States could step forward to promote commodities and markets that don’t rely on deforestation. These include clamping down on illegal deforestation through tougher import laws, use our technical expertise and resources to bulk up the transparency of of both global agricultural practices and supply chains, and push reforms to both foreign aid and trade agreements.
Finally — and it’s a bit of a second-order effect — another thing the U.S. government could do to help is completely rethink its mandated blend of biofuel in our gasoline supplies. The current policy drives up the demand (and thus the profitability) of corn, soy, and other biofuel stocks, encouraging more deforestation both here in the states and in rainforests around the world to make room for cropland.
So that’s where we are with deforestation. It’s just a slice of the possible solutions, but it’s not a negligible slice. And we aren’t doing enough to make full use of it.