Company lists · Data refreshed September 2026

Top 25 Climate change organizations based in the United States

RevenueBase identified 1,376 climate change organizations headquartered in the United States as of September 2026 and tracks 22,089 professional contacts across them, including 7,322 with verified work emails. Washington is the largest hub.

This list covers climate change organizations headquartered in the United States, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 19, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 19, 2026 86% judged on-target in blind review
1,376Companies
22,089Contacts tracked
7,322Verified emails
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The 25 largest climate change organizations based in the United States

Ranked by team size
Top 25 of 1,376 climate change organizations based in the United States, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to climate change organizations: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceWashington, DC, United StatesHQ checked Sep 19, 20261,001-5,0001,359 contacts →

Partial evidence

“WRI works to improve people’s lives, protect and restore nature and stabilize the climate.”

Source: RevenueBase Database · checked Sep 19, 2026
2Partial evidenceNew York, NY, United StatesHQ checked Sep 19, 20261,001-5,0001,352 contacts →

Partial evidence

“We are Environmental Defense Fund, a leading environmental nonprofit focused on stabilizing the climate while helping build strong and healthy communities.”

Source: RevenueBase Database · checked Sep 19, 2026
3Indirect evidenceOakland, CA, United StatesHQ checked Sep 19, 2026501-1,0001,069 contacts →

Indirect evidence

“At the Sierra Club, we believe in the power of togetherness.”

Source: RevenueBase Database · checked Sep 19, 2026
4Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 19, 2026n/a759 contacts →

Partial evidence

Climatebase is the community for climate & sustainability professionals, and the world's #1 platform for green jobs.”

Source: RevenueBase Database · checked Sep 19, 2026
5Partial evidenceArlington, VA, United StatesHQ checked Sep 19, 202651-200368 contacts →

Partial evidence

“Rare is a global leader in driving social change for people and nature.”

Source: RevenueBase Database · checked Sep 19, 2026
6Indirect evidenceSan Francisco, CA, United StatesHQ checked Sep 19, 202651-200288 contacts →

Indirect evidence

“CPI is an analysis and advisory organization with deep expertise in finance and policy.”

Source: RevenueBase Database · checked Sep 19, 2026
7Indirect evidenceBoston, MA, United StatesHQ checked Sep 19, 202651-200241 contacts →

Indirect evidence

“Ceres is a nonprofit advocacy organization working to accelerate the transition to a cleaner, more just, and resilient world.”

Source: RevenueBase Database · checked Sep 19, 2026
8Partial evidenceArlington, VA, United StatesHQ checked Sep 19, 2026201-500224 contacts →

Partial evidence

“We are in the business of conservation, creating innovative solutions that drive nature-based action for climate protection, sustainable economies and vibrant communities.”

Source: RevenueBase Database · checked Sep 19, 2026
9Partial evidenceWashington, DC, United StatesHQ checked Sep 19, 2026n/a222 contacts →

Partial evidence

“Sunrise is a movement of young people uniting to stop the climate crisis.”

Source: RevenueBase Database · checked Sep 19, 2026
10Partial evidenceWashington, DC, United StatesHQ checked Sep 19, 202651-200221 contacts →

Partial evidence

“Founded in 2007, Verra is a global mission-driven nonprofit organization that develops and manages the leading standards for climate and sustainable development.”

Source: RevenueBase Database · checked Sep 19, 2026
11Partial evidenceSan Francisco, CA, United StatesHQ checked Sep 19, 2026201-500205 contacts →

Partial evidence

ClimateWorks Foundation is a catalyst for accelerating climate progress, driving bold solutions that benefit people and the planet.”

Source: RevenueBase Database · checked Sep 19, 2026
12Partial evidenceFalmouth, MA, United StatesHQ checked Sep 19, 202651-200156 contacts →

Partial evidence

“Woodwell Climate Research Center conducts science for solutions at the nexus of climate, people, and nature-solutions that are urgently needed to propel us toward a more…”

Source: RevenueBase Database · checked Sep 19, 2026
13Indirect evidenceMadison, WI, United StatesHQ checked Sep 19, 202651-200146 contacts →

Indirect evidence

“We're a nonprofit headquartered in Madison, WI with an office in Chicago and remote staff across the U.S.”

Source: RevenueBase Database · checked Sep 19, 2026
14Indirect evidenceWashington, DC, United StatesHQ checked Sep 19, 202611-50144 contacts →

Indirect evidence

“EARTHDAY.ORG’s mission is to diversify, educate and activate the environmental movement worldwide.”

Source: RevenueBase Database · checked Sep 19, 2026
15Indirect evidenceSanta Cruz, CA, United StatesHQ checked Sep 19, 202651-200140 contacts →

Indirect evidence

“Ecology Action is an award-winning California 501(c)(3) non-profit that’s been inspiring sustainable community actions since 1970.”

Source: RevenueBase Database · checked Sep 19, 2026
16Partial evidenceSan Rafael, CA, United StatesHQ checked Sep 19, 202651-200127 contacts →

Partial evidence

“SEI is an environmental nonprofit that builds leaders to accelerate climate solutions.”

Source: RevenueBase Database · checked Sep 19, 2026
17Indirect evidenceWashington, DC, United StatesHQ checked Sep 19, 202611-50124 contacts →

Indirect evidence

“The NDC Partnership brings together 270 members, including more than 140 countries, developed and developing, and more than 110 institutions to create and deliver on ambitious…”

Source: RevenueBase Database · checked Sep 19, 2026
18Indirect evidenceWashington, DC, United StatesHQ checked Sep 19, 202651-20097 contacts →

Indirect evidence

“Founded in 1971, Greenpeace began when a small group of activists sailed from Vancouver to protest nuclear testing at Amchitka, Alaska.”

Source: RevenueBase Database · checked Sep 19, 2026
19Strong evidenceBoulder, CO, United StatesHQ checked Sep 19, 202611-5095 contacts →

Strong evidence

“Protect Our Winters is a 501(c)(3) nonprofit that helps passionate outdoor people protect the places and experiences they love from climate change.”

Source: RevenueBase Database · checked Sep 19, 2026
20Strong evidenceDenver, CO, United StatesHQ checked Sep 19, 202651-20093 contacts →

Strong evidence

“Every day, we see more heartbreaking evidence of the damage being done to our planet: climate change, plastic pollution, wildlife disappearing forever.”

Source: RevenueBase Database · checked Sep 19, 2026
21Strong evidenceWashington, DC, United StatesHQ checked Sep 19, 202651-20091 contacts →

Strong evidence

“The American Council for an Energy-Efficient Economy a nonprofit research organization, develops policies to reduce energy waste and combat climate change.”

Source: RevenueBase Database · checked Sep 19, 2026
22Partial evidenceNew York, United StatesHQ checked Sep 19, 202611-5091 contacts →

Partial evidence

“The Women and Climate community provides a joyful and safe space for women and nonbinary professionals from around the world to learn and talk about climate.”

Source: RevenueBase Database · checked Sep 19, 2026
23Partial evidenceSan Mateo, CA, United StatesHQ checked Sep 19, 202651-20083 contacts →

Partial evidence

“Jupiter is the trusted leader in climate risk analytics for organizations looking to strengthen their climate resilience.”

Source: RevenueBase Database · checked Sep 19, 2026
24Indirect evidenceKansas City, MO, United StatesHQ checked Sep 19, 202611-5083 contacts →

Indirect evidence

“Bridging The Gap brings people together to protect and restore the web of life on Earth and foster inclusive, thriving communities through environmental education, innovation, and…”

Source: RevenueBase Database · checked Sep 19, 2026
25Strong evidenceBoulder, CO, United StatesHQ checked Sep 19, 202651-20082 contacts →

Strong evidence

“Western Resource Advocates fights climate change and its impacts to sustain the environment, economy, and people of the West.”

Source: RevenueBase Database · checked Sep 19, 2026

Showing 25 of 1,376 climate change organizations based in the United States

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Climate change organizations based in the United States at a glance

As of Sep 19, 2026
33.1%Verified-email coverage
16.1Average contacts per company
1-10Median size (employees)
8.9%Largest-city concentration · Washington
Sep 19, 2026Page data refreshed

Companies by employee count

1-10
894
11-50
352
51-200
89
201-500
17
501-1,000
8
1,001-5,000
9
5,001-10,000
2
10001+
5

Email recency for this list is measured worldwide rather than for United States, so it is reported there. Company counts and contact totals on this page are exact for United States, over 1,376 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among climate change organizations, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source
The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United States whose own description of what they do matches “climate change organizations”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names climate change organizations), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among climate change organizations, and records with no verified work email. Companies headquartered outside United States are excluded even when they keep an office there.
Match quality
In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
Ranking
Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
Verification
Every listed company carries at least one verified work email, 7,322 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh
This page's figures were pulled from the company graph on September 19, 2026. Lists refresh periodically as the graph is re-checked.
Corrections
Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names climate change organizations, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many climate change organizations are there based in the United States?

RevenueBase identified 1,376 climate change organizations headquartered in the United States as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

World Resources Institute, headquartered in Washington, tops this list with the largest team on record.

Which city has the most climate change organizations?

Washington leads with 122 headquartered companies, followed by New York (120) and San Francisco (76).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 7,322 verified decision-maker contacts tracked across these 1,376 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 19, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.