Company lists · Data verified August 2026

Top 25 Climate change consulting firms based in the United States

Name: 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 Verified Aug 28, 2026 2,563 companies tracked

There are 2,563 climate change consulting firms headquartered in the United States (RevenueBase, August 2026). RevenueBase tracks 59,828 professional contacts across them, including 29,270 with verified work emails and 23,315 with mobile numbers. New York is the largest hub.

This list covers 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. Data current as of August 28, 2026.

2,563Companies

59,828Contacts tracked

29,270Verified emails

23,315Mobile numbers

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

Ranked by team size

Top 25 of 2,563 climate change consulting firms based in the United States, ranked by team size, largest first. Data verified Aug 28, 2026. Click a count to unlock that company's people.
#	Company	HQ	Employees	Contacts	Verified emails
1	Golder	Houston, TX	5,001-10,000	3,183	1,044
2	APTIM	Wichita, KS	1,001-5,000	2,644	1,098
3	Geosyntec Consultants	Boca Raton, FL	1,001-5,000	2,392	1,594
4	Baringa	New York, NY	1,001-5,000	2,198	1,548
5	Ricardo	California, MD	1,001-5,000	2,111	955
6	Hazen And Sawyer	Raleigh, NC	1,001-5,000	2,105	1,457
7	Swca Environmental Consultants	Phoenix, AZ	1,001-5,000	1,618	1,159
8	Montrose Environmental Group	Little Rock, AR	1,001-5,000	1,516	846
9	Apex Companies	Rockville, MD	1,001-5,000	1,146	591
10	Haley & Aldrich	Burlington, MA	501-1,000	1,128	789
11	Verdantas	Toledo, OH	1,001-5,000	1,127	795
12	Braun Intertec Corporation	Amarillo, TX	1,001-5,000	1,054	691
13	Trinity Consultants	Dallas, TX	1,001-5,000	949	615
14	DUDEK	Encinitas, CA	501-1,000	792	453
15	The Foth Companies	Marion, MA	501-1,000	790	537
16	Environmental Science Associates	Petaluma, CA	501-1,000	725	517
17	Inerco	Delaware	1,001-5,000	682	90
18	Antea Group USA	White Plains, NY	1,001-5,000	658	6
19	EBI Consulting	Springfield Township, PA	501-1,000	530	351
20	Rincon Consultants	San Diego, CA	501-1,000	483	312
21	Anchor QEA	Columbia, MD	501-1,000	478	329
22	Groundwater & Environmental Services, INC	Amherst, NY	201-500	452	229
23	ROUX	Houston, TX	201-500	435	311
24	TRIO	Mclean, VA	201-500	382	245
25	P2s	Irvine, CA	201-500	370	208

Showing 25 of 2,563 climate change consulting firms based in the United States

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Climate change consulting firms based in the United States at a glance

As of Aug 28, 2026

1-10Median size (employees)

New YorkLargest hub · 138 HQs

23,315Contacts with mobile numbers

156Emails re-verified in last 30 days

Companies by employee count

1-10

1,712

11-50

614

51-200

155

201-500

501-1,000

1,001-5,000

5,001-10,000

Climate change consulting firms by metro

Metro	Companies
Climate change consulting firms in New York	138
Climate change consulting firms in Washington	98
Climate change consulting firms in Houston	69
Climate change consulting firms in San Francisco	68
Climate change consulting firms in Chicago	54
Climate change consulting firms in Seattle	49
Climate change consulting firms in Los Angeles	47

How this list was built

Source: The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion: Companies whose own business descriptions match “climate change consulting firms”, with match quality audited by blind human judging, and headquartered in the United States.
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: Contact records re-verify on a rolling cadence; 156 contacts on this list were re-verified in the last 30 days.
Refresh: Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

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

There are 2,563 climate change consulting firms headquartered in the United States as of August 2026 (RevenueBase).

What is the largest company on this list?

Golder, headquartered in Houston, tops this list with the largest team on record.

Which city has the most climate change consulting firms?

New York leads with 138 headquartered companies, followed by Washington (98) and Houston (69).

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 29,270 verified decision-maker contacts tracked across these 2,563 companies.

How current is this list?

The list is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 2026.

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About this data

RevenueBase is a B2B contact data platform. Its company graph covers 21.3 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, the same data that powers RevenueBase's B2B data products and the free research portal.