If you’re reading this, chances are you care a lot about fighting climate change, and that’s great. Maybe you’re thinking about making a donation to the cause as you watch wildfires burning in California, ice shelves shattering in the Arctic, and glaciers breaking loose in Antarctica, all at the same time.

Climate change is the biggest emergency facing humanity. Our global response to it has been, in a word, pathetic. Over the past decade, our carbon dioxide emissions have actually risen 11 percent. We need to reverse that trend — and fast.

The trouble is, it can be genuinely hard to figure out how to direct your money wisely if you want to reduce greenhouse gas emissions. There’s a glut of environmental organizations out there and a lack of rigorous research on their impacts and cost-effectiveness, though that’s beginning to change with the arrival of new evaluators like Giving Green and ImpactMatters.

I’ve written before about how billionaire philanthropists can spend their money to fight climate change. But let’s face it: Most of us are not billionaires. While they can afford to spend influential sums on, say, trying to get a Democrat elected president, we might have only $10 or $100 to spend.

So if you’re in this camp and you want to have the greatest impact possible per dollar donated to the fight against climate change, where should you give?

Below is a list of six of the most high-impact, cost-effective, and evidence-based organizations. (I’m not including bigger-name groups, such as the Environmental Defense Fund or the Sierra Club, because most big organizations are already relatively well-funded.) The six groups here seem to be doing something especially promising in the light of certain criteria: importance, tractability, and neglectedness.

Important targets for change are ones that drive a big portion of global emissions. Tractable problems are ones where we can actually make progress right now. And neglected problems are ones that aren’t already getting a big influx of cash from other sources like the government or philanthropy, and hence could really use money from people like us.

Founders Pledge, an organization that guides entrepreneurs committed to donating a portion of their proceeds to effective charities, used these same criteria to assess climate organizations. Its comprehensive report, released in 2018, informed my research and the list below. As in that report, I’ve chosen to look at groups focused on mitigation (tackling the root causes of climate change by reducing emissions) rather than adaptation (decreasing the suffering from the impacts of climate change). Both are important, but the focus of this piece is preventing further catastrophe.

I’ve also intentionally selected organizations that are tackling this problem on different levels. Some advocate for high-level policy change or engage in long-term research, while others are achieving immediate emissions reductions through activities like stopping deforestation.

Dan Stein, director of the Giving Green initiative at IDinsight, an organization that uses data and evidence to combat poverty worldwide, says we should have a diverse portfolio of mitigation strategies. “There should be some short-term projects that give us certainty about reducing emissions now,” he told me. “But I also buy the argument that that’s not going to be enough — we need some moonshot projects.”

It’s very difficult to do a comparative cost-effectiveness analysis of different climate projects, and experts freely admit they’re not 100 percent sure they’ve made the best recommendations. Sometimes they’ll change their recommendations as new evidence comes to light. Likewise, I may update this piece as more information becomes available.

With that in mind, here are the organizations where your money will likely do the most good.

1) Coalition for Rainforest Nations

What it does: The Coalition for Rainforest Nations is unique in that it’s an intergovernmental organization of over 50 rainforest nations around the world, from Ecuador to Bangladesh to Fiji. It was formed after Papua New Guinea’s Prime Minister Michael Somare gave a speech in 2005, and since then it’s been partnering directly with governments and communities to protect their rainforests.

The Coalition championed something called the Reducing Emissions from Deforestation and Forest Degradation (REDD+) mechanism. Among other things, it ensures developing countries get paid if they can show that they’ve been preventing deforestation, a huge source of greenhouse gas emissions, and environmental degradation. This was folded into the UN Framework Convention on Climate Change and enshrined in Article 5 of the Paris agreement. The Coalition now concentrates on implementing REDD+ and on increasing public and private funding for it.

Why you should consider donating: This group is believed by Founders Pledge to have had a huge impact on reducing emissions through REDD+. The group also played a big role in securing an agreement on forestry in the Paris agreement.

According to Founders Pledge’s cost-effectiveness model from 2018, a donation of just 12 cents to the Coalition for Rainforest Nations will avert approximately a metric ton of CO2 (or the equivalent in other greenhouse gases). This means that if you donate $100, you can avert around 857 metric tons of CO2.

These are definitely just estimates, but still, that’s pretty damn good! For comparison, the average American causes around 16 metric tons of emissions per year. And most organizations can’t avert a metric ton for less than $2.

If you like the sound of this, you can donate here.

2) Clean Air Task Force

What it does: The Clean Air Task Force is a US-based non-governmental organization (NGO) that has been working to reduce air pollution since its founding in 1996. It led a successful campaign to reduce the pollution caused by coal-fired power plants in the US, helped limit the US power sector’s CO2 emissions, and helped establish regulations of diesel, shipping, and methane emissions.

Why you should consider donating: In addition to its seriously impressive record of success and the high quality of its research, the Clean Air Task Force does well on the neglectedness criterion: It often concentrates on targeting emissions sources that are neglected by other environmental organizations, and on scaling up deployment of technologies that are crucial for decarbonization yet neglected by NGOs and governments. For example, since 2009 it’s been working on a campaign for tax incentives for carbon capture and storage.

Founders Pledge estimates that a donation to this group would avert CO2 at a rate of $1 per metric ton. So, if you donate $100, you can avert around 100 metric tons of CO2 (or the equivalent in other greenhouse gases). Not bad!

You can donate here.

3) The Clean Energy Innovation program at the Information Technology and Innovation Foundation

What it does: The Information Technology and Innovative Foundation, a highly regarded US think tank, runs the Clean Energy Innovation program. That program looks into smart clean energy research and development and the effectiveness of increasing spending in that space, then advises policymakers on the best course of action.

Why you should consider donating: Let’s Fund, which is guided by “the principles of Effective Altruism” in its recommendations, argues it’s the best place to donate for climate change.

Here’s why: By 2040, around 75 percent of all emissions will come not from the US or the EU, but from emerging economies like China and India. So in addition to reducing emissions at home, we need to make it likelier that those countries will reduce their emissions, too. A great way to do that is to stimulate innovation that will make clean energy technology cheaper everywhere. For example, if you bring down the cost of low-carbon technology in the US, you can make it competitive with fossil fuels in China and India, encouraging its use. That’s called a global technology spillover.

Let’s Fund compared 10 innovation-stimulating policies (like carbon taxes, deployment subsidies, and cutting fossil fuel subsidies) and found that increasing budgets for public clean energy R&D is the most effective.

This sort of R&D is also neglected; only 0.02 percent of world gross domestic product is spent on it annually. (In the meantime, we’re spending 300 times that — 6 percent — on the energy we use up!)

In advanced economies like the US and EU, we can unilaterally increase how much we spend on R&D — no international coordination necessary. That, Let’s Fund says, “makes this much more politically tractable than carbon taxes.” And as my colleague David Roberts has written, “Innovation is perhaps the one climate policy that virtually everyone agrees on, across the ideological spectrum. Even US Republicans support it, at least notionally.”

You can donate here.

4) Rainforest Foundation US

What it does: Rainforest Foundation US works to protect the rainforests of Central and South America by partnering directly with folks on the front lines: indigenous people in Brazil, Peru, Panama, and Guyana, who are deeply motivated to protect their lands. The foundation supplies them with legal support as well as technological equipment and training so they can use smartphones, drones, and satellites to monitor illegal loggers and miners, and take action to stop them.

Why you should consider donating: Rainforest Foundation US has shown an unusual commitment to rigorous evaluation of its impact by inviting Columbia University researchers to conduct a randomized controlled trial in Loreto, Peru. Starting in early 2018, researchers collected survey data and satellite imagery from 36 communities partnered with the foundation and 40 control communities. The preliminary results are promising.

“We see tentative findings that along the deforestation frontier — where deforestation was most likely to occur — there are reductions in the rate of deforestation,” said Tara Slough, the Columbia University researcher leading the study, in a presentation last year.

Given that we’ve lately seen massive fires and a surge of deforestation in the Amazon rainforest, an ecosystem on which the global climate depends, it now seems like an especially good time to directly support the indigenous people who are holding the front line for all of us.

You can donate here.

5) Sandbag

What it does: Based in London and Brussels, Sandbag is a nonprofit think tank that uses data analysis to help build evidence-based climate policy. It advocates for carbon capture and storage in the EU, pushes for strong carbon pricing, and works to accelerate the coal phase-out in Europe so as to ensure all plants are closed before 2030.

Why you should consider donating: Since it focuses on the EU — which is not projected to be one of the biggest emitters and so is not as high-priority a region as Asia or Africa — Sandbag scores lower on the importance criterion than the groups mentioned above. But it’s still among the best groups out there (it made the Founders Pledge shortlist), particularly because it’s one of the few European charities working on carbon capture and storage, a sorely neglected mitigation strategy. And it works to change European legislation on climate by working with and influencing key policymakers.

You can donate by going here and clicking on the section on funding.

6) Climate Emergency Fund

What it does: The Climate Emergency Fund is different from the groups listed above. It was founded recently — July 2019 — with the goal of quickly getting money to groups engaged in climate protest. It has already raised and disbursed several hundreds of thousands of dollars in grants to groups it has vetted. The grantees range from the well-established 350.org to the fledgling Extinction Rebellion, an activist movement that uses nonviolent civil disobedience — like filling the streets and blocking intersections — to demand governments do more to stave off mass extinction.

Why you should consider donating: Because it’s relatively new, the Climate Emergency Fund has less of an evidence base than the organizations listed above, so we’ll have to monitor its impact and cost-effectiveness. But it offers something important: immediacy. As David Roberts wrote for Vox:

The money is going to everything from hiring organizers to buying signs and bullhorns to organizing school trips. A second round of more than 30 grants is in the works, representing over $2 million more. The fund is currently raising money, accepting donations large and small. ... [The founders] came together around a shared conviction that street protest is both crucially important to climate politics and a longtime blind spot for environmental philanthropy.

And there’s evidence that focusing on movement-building is essential in the climate fight. If you’re skeptical that street protest can make a difference, consider Harvard political scientist Erica Chenoweth’s research. She’s found that if you want to achieve systemic social change, you need to mobilize 3.5 percent of the population, a finding that helped inspire Extinction Rebellion. That’s not an impossible proportion of people to get into the streets — particularly if the activists doing the work get funded.

Bill McKibben, co-founder of 350.org, recently told me that building the climate movement is crucial because although we’ve already got some good mitigation solutions, we’re not deploying them fast enough. “That’s the ongoing power of the fossil fuel industry at work. The only way to break that power and change the politics of climate is to build a countervailing power,” he said. “Our job — and it’s the key job — is to change the zeitgeist, people’s sense of what’s normal and natural and obvious. If we do that, all else will follow.”

You can donate to the Climate Emergency Fund here.

Aside from donating, there are many other ways you can help

It’s worth noting that there are plenty of ways to use your skills to combat climate change. And many don’t cost a cent.

If you’re a writer or artist, you can use your talents to convey a message that will resonate with people. If you’re a religious leader, you can give a sermon about climate and run a collection drive to support one of the groups above. If you’re a teacher, you can discuss this issue with your students, who may influence their parents. If you’re a good talker, you can go out canvassing for a politician you believe will make the right choices on climate.

If you’re, well, any human being, you can consume less. You can reduce your energy use, reduce how much stuff you buy (did you know plastic packaging releases greenhouse gases when exposed to the elements?), and reduce how much meat you consume.

Research shows that it’s very difficult to “convert” people to vegetarianism or veganism through information campaigns, which is one reason why I did not recommend donating to such campaigns (there are more cost-effective options). But now that you can get Impossible Whoppers and Beyond Burgers delivered right to your door, you can easily transition to a more plant-based diet without sacrificing on taste.

You can, of course, also volunteer with an activist group — whether it’s Extinction Rebellion, the Sunrise Movement, or Greta Thunberg’s Fridays for Future — and put your body in the street to nonviolently disrupt business as usual and demand change.

The point is that activism comes in many forms. It’s worth taking some time to think about which one (or ones) will allow you, with your unique capacities and constraints, to have the biggest positive impact. But at the end of the day, don’t let the perfect be the enemy of the good: It’s best to pick something that seems doable and get to work.

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