Company lists · Data refreshed September 2026

Top 25 Sustainability and climate change consulting firms based in the United States

Name: Sustainability and climate change consulting firms based in the United States
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 2,744 companies tracked

RevenueBase identified 2,744 sustainability and climate change consulting firms headquartered in the United States as of September 2026 and tracks 62,904 professional contacts across them, including 31,370 with verified work emails. New York is the largest hub.

This list covers sustainability and climate change consulting firms 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 21, 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 21, 2026 86% judged on-target in blind review

2,744Companies

62,904Contacts tracked

31,370Verified emails

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The 25 largest sustainability and climate change consulting firms based in the United States

Ranked by team size

Top 25 of 2,744 sustainability and climate change consulting firms based in the United States, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to sustainability and climate change consulting firms: 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	WSP In The U.S	Indirect evidence	New York, NY, United StatesHQ checked Sep 21, 2026	10001+	9,318 contacts →
	Indirect evidence “What if you could shape built and natural environments – and the future of those that use them?” Source: RevenueBase Database · checked Sep 21, 2026
2	APTIM	Indirect evidence	Baton Rouge, LA, United StatesHQ checked Sep 21, 2026	1,001-5,000	2,639 contacts →
	Indirect evidence “APTIM enhances the quality of the environment, wellbeing of people, resilience of communities, and opportunity for employees to make a difference, not just a living.” Source: RevenueBase Database · checked Sep 21, 2026
3	Mckinstry	Partial evidence	Seattle, WA, United StatesHQ checked Sep 21, 2026	1,001-5,000	2,213 contacts →
	Partial evidence “We're a national construction and energy services company dedicated to innovating the waste and climate harm out of the built environment.” Source: RevenueBase Database · checked Sep 21, 2026
4	Swca Environmental Consultants	Partial evidence	Phoenix, AZ, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,629 contacts →
	Partial evidence “Founded on a commitment to sound science and creative solutions, SWCA is a leader in environmental and management consulting services.” Source: RevenueBase Database · checked Sep 21, 2026
5	Montrose Environmental Group	Indirect evidence	Little Rock, AR, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,529 contacts →
	Indirect evidence “Onterris (formerly Montrose Environmental Group) was one of the first to see environmental responsibility as not just an imperative but as a strategic asset.” Source: RevenueBase Database · checked Sep 21, 2026
6	Adec Innovations	Indirect evidence	Irvine, CA, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,304 contacts →
	Indirect evidence “ADEC Innovations seamlessly delivers fully integrated, cost-effective industry expertise, business process & data management, and software services.” Source: RevenueBase Database · checked Sep 21, 2026
7	Halcrow	Indirect evidence	Dallas, TX, United StatesHQ checked Sep 21, 2026	10001+	1,256 contacts →
	Indirect evidence “Halcrow is now Jacobs.” Source: RevenueBase Database · checked Sep 21, 2026
8	OLA	Strong evidence	Austin, TX, United StatesHQ checked Sep 21, 2026	n/a	1,145 contacts →
	Strong evidence “OLA Sustainability, LLC OLA Sustainability is a consulting firm that focuses on integrating sustainable practices into commercial and multifamily design projects.” Source: RevenueBase Database · checked Sep 21, 2026
9	Verdantas	Indirect evidence	Tampa, FL, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,139 contacts →
	Indirect evidence “At Verdantas, we blend engineering and environmental science together with advanced technology and world-renowned labs to create solutions with the big picture in mind.” Source: RevenueBase Database · checked Sep 21, 2026
10	Apex Companies	Indirect evidence	Rockville, MD, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,137 contacts →
	Indirect evidence “Who is Apex?” Source: RevenueBase Database · checked Sep 21, 2026
11	Braun Intertec Corporation	Indirect evidence	Minneapolis, MN, United StatesHQ checked Sep 21, 2026	1,001-5,000	1,065 contacts →
	Indirect evidence “At Braun Intertec, we work at the intersection of the natural and built environments, combining science, technology, and engineering.” Source: RevenueBase Database · checked Sep 21, 2026
12	Trinity Consultants	Indirect evidence	Dallas, TX, United StatesHQ checked Sep 21, 2026	1,001-5,000	961 contacts →
	Indirect evidence “Trinity Consultants is a global team of experts helping organizations solve complex challenges in environmental compliance, ecological protection, infrastructure performance, and…” Source: RevenueBase Database · checked Sep 21, 2026
13	Parametrix	Indirect evidence	Seattle, WA, United StatesHQ checked Sep 21, 2026	501-1,000	880 contacts →
	Indirect evidence “At Parametrix, we help our clients imagine what's possible.” Source: RevenueBase Database · checked Sep 21, 2026
14	Energy Solutions	Strong evidence	Oakland, CA, United StatesHQ checked Sep 21, 2026	201-500	772 contacts →
	Strong evidence “Our mission is simple - to combat climate change through market-based, cost-effective energy, carbon, and water management solutions that make big impacts.” Source: RevenueBase Database · checked Sep 21, 2026
15	Climatebase	Strong evidence	San Francisco, CA, United StatesHQ checked Sep 21, 2026	n/a	759 contacts →
	Strong evidence “Climatebase is the community for climate & sustainability professionals, and the world's #1 platform for green jobs.” Source: RevenueBase Database · checked Sep 21, 2026
16	Psomas	Indirect evidence	Los Angeles, CA, United StatesHQ checked Sep 21, 2026	501-1,000	748 contacts →
	Indirect evidence “Our award-winning projects are produced through innovation, creativity, and technical expertise.” Source: RevenueBase Database · checked Sep 21, 2026
17	Environmental Science Associates	Partial evidence	San Francisco, CA, United StatesHQ checked Sep 21, 2026	501-1,000	732 contacts →
	Partial evidence “ESA is a 100% employee-owned environmental consulting firm.” Source: RevenueBase Database · checked Sep 21, 2026
18	Uniqus Consultech INC	Strong evidence	San Jose, CA, United StatesHQ checked Sep 21, 2026	501-1,000	675 contacts →
	Strong evidence “Uniqus Consultech is an AI and global tech-enabled consulting company that specializes in Accounting & Reporting Consulting, Governance, Risk & Compliance, Sustainability &…” Source: RevenueBase Database · checked Sep 21, 2026
19	Antea Group USA	Partial evidence	St Paul, MN, United StatesHQ checked Sep 21, 2026	1,001-5,000	658 contacts →
	Partial evidence “Antea Group is an international engineering and environmental consulting firm specializing in full-service solutions in the fields of environment, health and safety, and…” Source: RevenueBase Database · checked Sep 21, 2026
20	Tighe & Bond	Partial evidence	Westfield, MA, United StatesHQ checked Sep 21, 2026	501-1,000	646 contacts →
	Partial evidence “Tighe & Bond is the Northeast’s leading engineering, environmental, planning, and design consulting firm.” Source: RevenueBase Database · checked Sep 21, 2026
21	EBI Consulting	Indirect evidence	Burlington, MA, United StatesHQ checked Sep 21, 2026	501-1,000	535 contacts →
	Indirect evidence “For 35 years we have been helping investors, lenders, owners, developers, contractors, and property managers reduce risk and optimize their built facilities, infrastructure and…” Source: RevenueBase Database · checked Sep 21, 2026
22	Watershed	Partial evidence	San Francisco, CA, United StatesHQ checked Sep 21, 2026	201-500	529 contacts →
	Partial evidence “Watershed is the enterprise sustainability platform.” Source: RevenueBase Database · checked Sep 21, 2026
23	Rincon Consultants	Partial evidence	Ventura, CA, United StatesHQ checked Sep 21, 2026	501-1,000	479 contacts →
	Partial evidence “Rincon Consultants is a multi-disciplinary environmental sciences, planning, and engineering consulting firm that provides quality professional services to government and industry.” Source: RevenueBase Database · checked Sep 21, 2026
24	Enhesa	Partial evidence	Arlington, VA, United StatesHQ checked Sep 21, 2026	201-500	474 contacts →
	Partial evidence “At Enhesa we empower the world’s largest businesses to achieve compliance, manage risk, and drive sustainability with clear, actionable insights.” Source: RevenueBase Database · checked Sep 21, 2026
25	Groundwater & Environmental Services, INC	Indirect evidence	Wall Township, NJ, United StatesHQ checked Sep 21, 2026	201-500	447 contacts →
	Indirect evidence “We are Groundwater & Environmental Services, Inc, better known as GES.” Source: RevenueBase Database · checked Sep 21, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: sustainability and climate change consulting firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names sustainability and climate change consulting firms.
Partial evidence: Its own public description names part of sustainability and climate change consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name sustainability and climate change consulting firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 2,744 sustainability and climate change consulting firms based in the United States

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Sustainability and climate change consulting firms based in the United States at a glance

As of Sep 21, 2026

49.9%Verified-email coverage

22.9Average contacts per company

1-10Median size (employees)

6.3%Largest-city concentration · New York

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

1,941

11-50

582

51-200

151

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

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 2,744 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 sustainability and climate change consulting firms, 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 “sustainability and climate change consulting firms”. 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 sustainability and climate change consulting firms), 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 sustainability and climate change consulting firms, 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, 31,370 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 21, 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.

Sustainability and climate change consulting firms by metro

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 sustainability and climate change consulting firms, 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 sustainability and climate change consulting firms are there based in the United States?

RevenueBase identified 2,744 sustainability and climate change consulting firms 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?

WSP In The U.S, headquartered in New York, tops this list with the largest team on record.

Which city has the most sustainability and climate change consulting firms?

New York leads with 173 headquartered companies, followed by Houston (79) and Washington (77).

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 31,370 verified decision-maker contacts tracked across these 2,744 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 21, 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.