Want to plant trees to offset fossil fuels? You'd need all of North and Central America, study finds
Planting trees has plenty of benefits, but this popular carbon-removal method alone can't possibly counteract the planet-warming emissions caused by the world's largest fossil-fuel companies. To do that, trees would have to cover the entire land mass of North and Central America, according to a study out Thursday.
Many respected climate scientists and institutions say removing carbon emissions — not just reducing them — is essential to tackling climate change. And trees remove carbon simply by "breathing." But crunching the numbers, researchers found that the trees' collective ability to remove carbon through photosynthesis can't stand up to the potential emissions from the fossil fuel reserves of the 200 largest oil, gas and coal fuel companies — there's not enough available land on Earth to feasibly accomplish that.
And even if there were, if those 200 companies had to pay for planting all those trees, it would cost $10.8 trillion, more than their entire combined market valuation of $7.01 trillion. The researchers also determined that the companies would be in the red if they were responsible for the social costs of the carbon in their reserves, which scientists compute around $185 per metric ton of carbon dioxide.
'The general public maybe understand offsetting to be a sort of magic eraser, and that's just not where we're at,' said Nina Friggens, a research fellow at the University of Exeter who co-authored the paper published in Communications Earth & Environment, a Nature Portfolio journal.
Carbon offsetting essentially means investing in tree planting or other environmental projects to attempt to compensate for carbon emissions. Trees are one of the cheapest ways to do this because they naturally suck up planet-warming carbon. Fossil fuel corporations, along with other companies and institutions, have promoted tree-planting as key part of carbon offset programs in recent years.
For example, TotalEnergies, a global energy company, said in a statement that it is 'investing heavily in carbon capture and storage (CCS) and nature-based solutions (NBS) projects.'
To do their calculations, the researchers looked at the 200 largest holders of fossil fuel reserves — the fuel that companies promise shareholders they can extract in the future — and calculated how much carbon dioxide would be released if this fuel is burned. The researchers also focused solely on tree planting because the expense and technological development needed for other forms of carbon capture are still mostly cost-prohibitive.
Forestry expert Éliane Ubalijoro, who was not involved with the research, called the study 'elegant.'
It 'gives people a sense of proportion around carbon,' said Ubalijoro, CEO of CIFOR-ICRAF, an international forestry research center.
But she cautioned against oversimplifying the equation by looking only at carbon capture, noting that tree planting done right can foster food security and biodiversity and protect communities from natural disasters.
The paper effectively makes the point that it's financially impossible to offset enough carbon to compensate for future fossil fuel burning, said Daphne Yin, director of land policy at Carbon180, where her team advocates for U.S. policy support for land-based carbon removal. And the idea that companies would ever be required to account for the downstream emissions from the fossil fuel they extract is a 'fantasy,' she said.
The idea of planting trees is appealing to the public and to politicians because it's tangible — people can literally see the carbon being incorporated into branches and leaves as a tree grows, Friggens said. But she says other methods shouldn't be overlooked — microbes underground store carbon too, but they can't be seen.
And it's a physically and mathematically inescapable fact, illustrated in part by this study, that there's no getting around it — we have to stop emitting carbon, said Jonathan Foley, the executive director of Project Drawdown, who also was not part of the study. Carbon emissions are like an overflowing bathtub, he says: Before you start cleaning up, you have to turn off the water.
'Trees are the sponges and the mops we use to clean up the mess," he said. "But if the taps are still running and the water's pouring out over the edges of your bathtub, destroying your bathroom and your home, maybe you've got to learn to turn off the taps too.'
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The Associated Press' climate and environmental coverage receives financial support from multiple private foundations. AP is solely responsible for all content. Find AP's standards for working with philanthropies, a list of supporters and funded coverage areas at AP.org.
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Plastic shopping bag policies are actually working, a new study suggests
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CNN
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Plastic shopping bag policies are actually working, a new study suggests
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Washington Post
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Plastic bag fees and bans help limit coastal litter, study finds
Plastic bag fees and bans are effective in limiting debris on U.S. shorelines, a new study reports, but even places with bag policies are seeing a greater prevalence of plastic bags on beaches and riverbanks. The study, published Thursday in the peer-reviewed journal Science, analyzed the relationship between policies on plastic bags and the litter collected in more than 45,000 shoreline cleanups. In communities with policies in place, the prevalence of plastic bags in the trash was 25 percent to 47 percent lower than in places without regulations. But plastic bags increased as a share of litter both in communities with policies and those without, the researchers noted. The policies appeared to contain that growth but not stop or reverse it. Measures targeting plastic bags aren't eliminating the problem, just slowing its growth, said Kimberly Oremus, one of the study's authors and an associate professor at the University of Delaware's School of Marine Science and Policy. The impact of the policies has been somewhat limited, Oremus said, because they can be patchy in what they regulate and are themselves a patchwork, with rules and enforcement varying from place to place. 'Most of these bans and fees don't cover every type of plastic bag,' she said. 'There's a lot of exceptions to them. It really depends on the state.' The goal of all these policies is the same: to limit the use of plastic bags, which can take centuries to decompose and, in the interim, can entangle wildlife and release microplastics and toxic chemicals into waterways. Some places have imposed 'bag taxes' or fees on customers using plastic bags. Other places have experimented with bans — though they might prohibit thin plastic bags (which are most likely to blow away and become trash) while allowing thicker ones, or they might leave restaurant takeout bags unregulated. Erin Murphy, manager of ocean plastics research at Ocean Conservancy, said the new report was 'the first large-scale study to systematically assess how plastic bag policies reduce the amount of plastic bag pollution in our environment.' Murphy was not involved in the analysis, but the researchers used her nonprofit group's data from shoreline cleanups between 2016 and 2023. That data provided a way to measure litter before and after policies were enacted and do comparisons with measurements in places without any regulations. Lead author and environmental economist Anna Papp said one of the key findings was the difference between broad policies, which appeared to limit plastic litter, versus partial bans, which resulted in the smallest and least precise effects. There was also some evidence that bag fees could have a greater effect than bans. But the researchers said that fees are also much less common than bans and that more research is needed to assess their relative effectiveness. The study also found that state-level policies had a greater impact than town-level measures, Oremus said. Larger-scale policies tend to be more robust, she said, because 'litter can travel between borders.' The analysis also showed that the largest reductions in trash occurred in places with high amounts of plastic bag pollution. 'Are you a place that struggles with litter?' Oremus said. 'Then, this might be a policy to consider.' Erin Hass, senior director of strategic alliances with the Plastics Industry Association, noted that plastic bags represent a fairly small portion of litter that winds up along U.S. shorelines. 'Even the study itself acknowledges that the top sources of beach litter are cigarette butts, food wrappers, bottle caps and beverage bottles — not plastic bags,' Hass said. 'Why are regulators isolating a single product while overlooking far more prominent contributors?' Bans could 'create unintended consequences,' Hass said. She noted that after the implementation of a bag ban in New Jersey, for example, thin plastic bags disappeared, but overall plastic consumption appeared to increase because of a switch to heavier reusable bags, which tended to be tossed after minimal use. 'If the goal is reducing marine debris and advancing sustainability, the smarter approach is to invest in scalable recycling systems, not sweeping bans that shift the problem rather than solve it,' she said.
