Over the past decade, research has emerged suggesting that ramping up reforestation around the world could make a substantial contribution to tackling climate change.
Studies have estimated that the CO2-absorbing power of newly planted trees could add up to mitigation “potential” of 10bn tonnes (GtCO2) per year – more than the annual emissions of the US.
Achieving this would require planting trees across 678m hectares – an area twice the size of India.
But the uncertainty around those figures is large due to a range of factors, such as where sufficient trees already exist, how much climate mitigation those trees offer and where people actually want additional trees to be planted.
In our new study, published in Nature Communications, we unpack eight years of research into reducing these uncertainties.
We have quantified, for example, how the carbon-sucking power of trees changes when you let forests grow back naturally versus planting monoculture or mixed-species plantations.
We figured out how much carbon could be removed at different price points and mapped where trees – somewhat counterintuitively – actually act to warm, rather than cool, our climate.
But, as we shrank the uncertainty, we also shrank the estimate itself.
Our research provides the most precise estimate of global reforestation area to date – 195m hectares, or 71% less than earlier estimates.
Reforesting an area this size could capture 2GtCO2 per year.
Mapping reforestation opportunity
Maps of global reforestation potential have been cited in thousands of scientific publications, inspired large-scale tree-planting movements and been used by the International Panel on Climate Change (IPCC) in its flagship reports.
However, they have also been very controversial.
Critics have pointed out, for example, that these maps failed to account for natural disturbances that prevent forest growth, ignored existing trees and overlooked the people that live, steward and often depend on those lands for their wellbeing.
In our new study, we resolved to produce a map that addresses these past critiques.
We began by searching for existing maps of reforestation “opportunity”.
Our search uncovered 89 such maps, although most of those we identified are national or sub-national. Some places – such as Brazil’s Atlantic Forest – have many maps, but we found that most of the globe was only covered by a single older, more controversial map.
The map below shows where we found existing maps at the global, regional, national and sub-national levels.
Thus, we set about creating a new global map that built upon the methods of past efforts, tackled prominent critiques and incorporated newly available layers.
Our new map accounts for albedo, for example – how restoring tree cover can, in some locations, actively heat the Earth, rather than cool it, by affecting how much sunlight is absorbed or reflected.
It excludes native grasslands and other ecosystems where carpeting the land with trees would harm biodiversity and exacerbate the risk of wildfire. And it layers in additional safeguards, such as food security, to ensure that reforestation outcomes are more likely to be beneficial to people.
These constraints left us with up to 195m hectares of reforestation opportunity across the world.
A reforestation ‘menu’
Not all reforestation opportunities are created equal – different communities may want to implement reforestation for different reasons, such as restoring floodplains or re-establishing iconic ecosystems that have been lost.
So, alongside the reforestation opportunity, our map shows other factors that communities or decisionmakers may use to help them prioritise areas for reforestation.
We show, for example, where natural regeneration may be most likely to occur and where biodiversity benefits may be greatest, given proximity to existing forest. We show where reforestation opportunity exists on slopes and floodplains – and therefore is more likely to provide benefits for the local watershed. We show places where people have strong rights and secure land tenure, to avoid exacerbating social inequities.
Perhaps unsurprisingly, it is hard to find places that tick all of these complex boxes. But, it is still possible to achieve multiple objectives in one location.
In fact, our study finds that 83% of reforestation opportunities occur close to existing forest, while 81% occur in places that are expected to have low conflicts with rural livelihoods.
More than half of the opportunity that we identify also occurs in countries with explicit restoration goals – places such as Brazil’s Atlantic Forest, where we are working with local partners and communities to restore 1.2m hectares of forest. Forest restoration there contributes to national climate goals, supports sustainable economic development and connects habitat for wildlife.
Alongside the paper, we present the Global Reforestation Hub, which allows users to explore this menu of reforestation options, drill down to reforestation potential at county level and see what opportunities meet a given set of objectives.
For example, a government interested in climate mitigation and protection from floods might use the tool to find the places within their country where both goals might be achieved via reforestation.
The screenshot below shows the Global Reforestation Hub. Countries are coloured by their total reforestation opportunity, from low (white) to high (dark blue). The table shows the amount of land available for – and the CO2 mitigation potential of – reforestation given different priorities and constraints.
Smaller can be better
Reforestation remains one of the most cost-effective climate removal options, but it cannot – and should not – happen everywhere.
While there are certainly opportunities to plant and regrow trees beyond what we have mapped here, we created these maps to show where the climate mitigation opportunities – and their co-benefits – are most concentrated.
Prioritising other motivations, such as human health, habitat for specific wildlife species or local considerations, would also increase the total reforestation opportunity area. For example, our maps don’t include the potential for reforestation in dense urban areas, but trees in those areas can be highly beneficial for human health.
Our study prioritised mapping opportunities for climate change mitigation – and we were deliberately conservative, erring on the side of caution when determining which places to include.
The result is a map that shows the places where reforestation offers both the greatest climate benefits and the fewest downsides for both people and nature.
During a year when the UN climate COP will be hosted in the most iconic forest of all, our study is less a critique of the pre-existing numbers and more an effort to create the most precise and pragmatic maps of reforestation potential. This can help ensure that we get the reforestation part of the climate equation right.
The post Guest post: Why the global area for regrowing trees is 71% smaller than thought appeared first on Carbon Brief.
Guest post: Why the global area for regrowing trees is 71% smaller than thought
Climate Change
Trump Administration Abandons Fight Against Wind Energy as Clean Energy Output Surges
The clean energy sector is showing resilience despite challenges thrown at it by a hostile White House, a recent report found. A string of legal victories has further dampened the Trump administration’s efforts to halt wind and solar power.
The Trump administration has abandoned its effort to halt wind energy projects across the United States and dropped its challenge to the court ruling that tossed President Donald Trump’s order freezing federal permitting and leasing for wind projects. States that challenged the order hailed the development as one of the most significant legal victories against the Trump White House’s campaign against the energy transition.
Trump Administration Abandons Fight Against Wind Energy as Clean Energy Output Surges
Amid reports that the government could weaken the UK’s electric vehicle (EV) targets, Carbon Brief analysis reveals the nation’s EV drivers are saving more than £1,100 a year in fuel costs, compared with running a petrol car.
Battery EVs (BEVs) are roughly four times more efficient than combustion-engine cars, making them far cheaper to run – particularly since the Iran crisis caused a spike in fossil-fuel prices.
The savings from driving BEVs are also more than three times higher than for “plug-in” hybrids (PHEVs), which evidence shows are mostly driven with their combustion engines.
In total, the more than 2m BEVs, 1m PHEVs and 100,000 electric vans on UK roads are saving drivers around £3bn a year, Carbon Brief’s analysis shows, as illustrated in the figure below.
In addition, these EVs are avoiding the need for nearly 2.5bn litres of fuel and cutting carbon dioxide (CO2) emissions by nearly 7m tonnes each year.
Despite recent news that EVs are now cheaper to buy than petrol cars, as well as having far lower running costs, BBC News says the government is “set to water down” its EV sales targets.
The broadcaster explains that the current goal, under the UK’s “zero-emissions vehicle” (ZEV) mandate, is for 80% of new car sales to be BEVs by 2030.
It says that the government is set to consult on weakening this to between 50% and 70%, following “lobbying” by carmakers and trade unions.
According to the Sunday Times, prime minister Keir Starmer “is understood to have overruled the energy secretary [Ed Miliband] after sustained pressure from industry, the Unite union and Peter Kyle, the business secretary”.
The car industry has consistently claimed there is insufficient demand for BEVs to meet the targets under the ZEV mandate, yet the government says manufacturers have “over-complied” to date. Independent analysts say the industry is on track to continue beating the ZEV mandate goals.
The industry has been able to beat its targets by using a wide range of “flexibilities”, which were introduced after a previous round of lobbying. These allow carmarkers to meet part of their EV targets by selling more efficient combustion cars, such as hybrids and plug-in hybrids.
The ZEV mandate is the single-largest part of the government’s plans to meet its legally binding climate goals over the next decade.
The advisory Climate Change Committee (CCC) previously warned that the extra flexibilities would result in a larger number of hybrids being sold, at the expense of battery EVs.
When it consulted on the ZEV mandate in 2023, the then-Conservative government noted that PHEVs do not deliver the cost and CO2 savings they are advertised with.
It pointed to “dramatic” differences between the performance of PHEVs in test cycles and what they deliver under real-world conditions.
In practice, less than a third of miles driven in PHEVs are fuelled by electricity, with petrol making up the rest. As a result, cost and CO2 savings from BEVs are three times larger than for PHEVs.
The post Analysis: UK’s EV drivers are now saving £1,100 each a year – and £3bn in total appeared first on Carbon Brief.
Analysis: UK’s EV drivers are now saving £1,100 each a year – and £3bn in total
Civil society groups have called for an investigation into the first carbon credits approved under a new UN mechanism, alleging the project is linked to Myanmar’s military junta – which the UN says is guilty of human rights abuses – and has “massively” overstated its climate impact.
The programme, which aims to cut emissions by distributing efficient cookstoves across Myanmar, received approval to issue around 650,000 carbon credits from the Article 6.4 Supervisory Body in February, in a landmark moment for the Paris Agreement’s carbon market. Only two projects have been given the green light by the mechanism’s regulator so far.
But two reports published last week, led by the Global Forest Coalition and Brussels-based NGO Carbon Market Watch, raised serious concerns about the project’s implementation in conflict zones where civilians have faced airstrikes and mass displacement as well as its emission-reduction calculations.
Project continued after military coup
Myanmar has been ravaged by a brutal civil war since the country’s military overthrew the democratically elected government in a coup d’état in February 2021. The military regime has attacked civilian populations, persecuted ethnic minorities and committed widespread sexual violence, among other serious human rights violations, the UN Special Rapporteur on the situation of human rights in Myanmar said in April.
The cookstove programme started in 2018 under the previous UN-run carbon offsetting scheme – the Clean Development Mechanism (CDM) – as a partnership between Myanmar’s Ministry of Natural Resources and Environmental Conservation (MONREC) and the Climate Change Center (CCC), a South Korean NGO, with investment from private South Korean firms.
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The project continued operating after the coup. For most of the period between 2021 and 2022 in which the issued credits were generated, MONREC was led by Colonel Khin Maung Yi, who was sanctioned by the European Union in 2021 for supporting the military regime, the Global Forest Coalition report said.
CCC acknowledged engaging with government authorities after the coup but said this “should not be interpreted as political endorsement” of the junta. The South Korean NGO added that abandoning the programme when political circumstances changed “would not necessarily have been the most responsible outcome for the households involved”.
Conflict prevents on the ground verification
The Global Forest Coalition report raised particular concerns about the project’s implementation in Myanmar’s central Dry Zone, including Sagaing Region, an anti-junta resistance stronghold that has been most heavily affected by the conflict and routinely targeted by airstrikes and violent attacks. The region accounts for more than a third of Myanmar’s 3.8 million internally displaced people.
The NGOs said that, in addition to ethical concerns about carbon credits being produced by the military government in an area actively affected by its attacks, this raises questions over the ability to effectively verify the climate integrity of the projects.
Before carbon credits are issued, external auditors need to validate the claims made by project developers and confirm that the emission reductions claimed are correct. This process usually includes site visits to a representative sample of households to check how the improved cookstoves are being used.
But, because of the “volatile political situation” in Myanmar, the auditing team was not able to leave the capital Yangon and could only speak to project participants remotely via Zoom, project documents show.
“Due to ongoing armed conflict on the ground, the data currently used to justify carbon credit issuance in Sagaing by the Burmese military junta is unverifiable and highly likely fraudulent,” said Zaw Tuseng, founder and president of the Myanmar Policy Institute, which contributed to the report, in a written statement. “This demands an immediate suspension of credit transfers until a neutral, conflict-sensitive audit can be conducted.”
“Exceptional circumstances”
CCC told Climate Home News that, although it recognises that on-site verification is “generally preferable, particularly in complex operating environments”, the decision to opt for remote controls was not taken “as a discretionary shortcut, but as an approved alternative under exceptional circumstances”.
The South Korean NGO added that it reviewed the feasibility of the project at community level “on an ongoing basis” and it “did not identify conflict-related incidents that directly affected project implementation activities in participating communities during the monitoring period”.
A spokesperson for the UN climate change body told Climate Home News that, when site access is not possible, the UN carbon credit mechanism allows for “alternative verification approaches while still maintaining conservative assumptions and environmental integrity safeguards”. “These provisions ensure that crediting can only proceed where evidence is reliable,” they added.
Contested methodology
Carbon markets are seen as an important channel to raise money to help low-income communities in developing countries switch to less polluting cooking methods, both reducing CO2 emissions and improving air quality. But several cookstove offsetting projects have faced criticism from researchers and campaigners who argue that climate benefits are often exaggerated and weak monitoring can undermine claims of real emission reductions.
The project in Myanmar uses a contested methodology developed under the earlier Kyoto Protocol that was rejected last year by The Integrity Council for the Voluntary Carbon Market (ICVCM), a watchdog that issues quality labels to carbon credit types, because it found it “insufficiently rigorous”.
EU carbon credits could supercharge world’s clean cooking push, France says
After transitioning from the CDM to the new mechanism, the project was required to apply “more conservative” assumptions to calculate emission reductions, which resulted in 40% fewer credits being issued, according to the UN climate change body.
“The result is consistent with environmental integrity requirements and ensures that each credited tonne genuinely represents a tonne reduced and contributes to the goals of the Paris Agreement,” Mkhuthazi Steleki, the South African chair of the Article 6.4 Supervisory Body, which oversees the mechanism, said in February.
Too many credits issued
But Carbon Market Watch claimed in a second report last week that, despite the adjustment, the project is still likely to issue seven times more credits than its real climate impact justifies, comparing its calculations with values from peer-reviewed scientific literature.
The biggest driver of the credit inflation, the group said, is the failure to account for “stacking” – the widespread practice of households using multiple stoves at the same time, including more polluting ones the project does not monitor.
Peer-reviewed science considers a stacking rate of 68% a conservative assumption, but the methodology used by the Myanmar programme makes no allowance for it at all, the report said.
CCC disputed those findings. In a written response to Climate Home News, it said the project was developed under methodologies approved within the UN climate framework and that external recalculations by researchers are not “determinative of the level of crediting achieved”.
The credits are expected to be used primarily by major South Korean polluters to meet obligations under the country’s emissions trading system – a move that will also enable the government to count those units toward emissions reduction targets in its nationally determined contribution (NDC), the UN climate body told Climate Home News.
Myanmar will use the remaining credits to achieve in part the goals of its own national climate plan under the Paris Agreement.
“Over-crediting, at any magnitude, cannot be compatible with the climate ambition of a world striving to limit global warming to 1.5ºC,” said Isa Mulder, an expert at Carbon Market Watch.
The post UN’s first Paris Agreement carbon credits face human rights and climate concerns appeared first on Climate Home News.
UN’s first Paris Agreement carbon credits face human rights and climate concerns
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