H. Leighton Steward
- Master of Science (Geology). 
H. Leighton Steward is the President and Chairman of Plants Need CO2, a group founded in 2009 with the mission “to educate the public on the positive effects of additional atmospheric CO2 and help prevent the inadvertent negative impact to human, plant and animal life if we reduce CO2.”
He is the Chairman of the Institute for the Study of Earth and Man (ISEM) Board of Trustees, and was Vice Chairman of the American oil and gas company Burlington Resources, Inc. until his retirement in 2000.
According to his profile at EOG Resources (formerly Enron Oil and Gas Company) where he is a director, Steward has extensive experience in the oil and gas exploration and production industry and has also worked with The Louisiana Land and Exploration Company as President, Chief Operating Officer and, Chairman of the Board and Chief Executive Officer from 1989 until its acquisition by Burlington Resources Inc. in 1997. 
Stance on Climate Change
“… carbon dioxide (CO2) is not a major contributor to current global warming nor to Earth's paleoclimates.” 
“More CO2 is needed to bolster plant life, which turns the gas into oxygen while also providing food.”
“Temperatures over time have fluctuated while CO2 levels have remained steady. What's more, temperature increases have historically led increases in CO2 levels.”
“Many, many reputable scientists believe that natural factors overpower the current influence of CO2 on global warming.”
“CO2 is a great airborne fertilizer, which, as its concentrations rise, causes additional plant growth and causes plants to need less water.”
“The warning level of CO2 in submarines isn't reached until the atmosphere has 8,000 parts per million of CO2.” 
“Humans have been fertilizing Earth’s greenery worldwide, but not with nitrogen-based fertilizer that runs into the rivers and oceans with very negative effects. We have been raising the level of CO2, which has no negative effect on any plant or animal life.” 
December 7, 2015
Leighton Steward appears as a “Key Scientist” in Marc Morano’s documentary film, Climate Hustle, which debuted on December 7, 2015, in Paris, France during the COP21 United Nations summit on climate change.  The film chiefly showcases Morano's personality, a range of discredited scientists, and no new factual information about climate change.
Other notable “Key Scientists” featured in Climate Hustle include: 
- Judith Curry
- Richard Tol
- Ivar Giaever
- Roy Spencer
- Patrick Moore
- Don Easterbrook
- Bob Carter
- Patrick Michaels
- Christopher Monckton
- Anthony Watts
- Walter Cunningham
- William Briggs
- Roger Pielke Sr.
- Robert Giegengack
- Caleb Rossiter
- Daniel Botkin
- John Theon
- Dennis Rancourt
January 12, 2015
H. Leighton Steward was a guest on the Heartland Institute's daily podcast where he describes his role in The Right Climate Stuff (TRCS) and his group's conclusion that “there is no convincing physical evidence of catastrophic man-caused global warming.”
September 26, 2014
H. Leighton Steward attends the “At the Crossroads; Energy & Climate Policy Summit” in Houston, Texas, hosted by the Texas Public Policy Foundation and The Heritage Foundation. Steward presents in “Panel V: Prosperity and Poverty,” with Calvin Beisner. 
July 7 - 9, 2014
DeSmogBlog has done in-depth research on the other speakers and sponsors from Heartland's ICCC9, which can be found here.
- The science that predicts the extent of anthropogenic global warming is not settled science.
- There is no convincing physical evidence of catastrophic anthropogenic global warming.
- Computer models need to be validated before being used in critical decision-making.
- Because there is no immediate threat of global warming requiring swift corrective action, we have time to study global climate changes and improve our prediction accuracy.
- The U.S. government is over-reacting to concerns about anthropogenic global warming.
- A wider range of solution options should be studied for global warming or cooling threats from any credible cause.
The group also presented at the Heartland Institute's 7th International Conference on Climate Change (ICCC-7) in 2012 in Chicago.
May 21 - 23, 2012
Steward was a speaker at the Heartland Institute's Seventh International Conference on Climate Change (ICCC7).
DeSmogBlog researched the co-sponsors behind Heartland's ICCC7 and found that they had collectively received over $67 million from ExxonMobil, the Koch Brothers and the conservative Scaife family foundations.
July 14, 2010
CO2 is Green, the sister organization of Steward's “Plants Need CO2” released an ad campaign fighting the president's cap-and-trade bill.
The ad, featured in The Washington Post, urges people to vote against “the president's cap-and-trade bill that will increase your cost of living and not change the climate.”
According to the ad, “The bill is based on the false premise that man-made CO2 is a major cause of climate change. Real, empirical evidence indicates it is not.” 
Steward is the spokesman and Chairman for CO2 is Green, as well as the President and Chair of Plants Need CO2.
May 16 - 18, 2010
Published “Fire, Ice and Paradise” which he describes as “an educational book for the non-scientist, including politicians, regarding the many factors affecting global climate change.”
“The bottom-line summary of the author's opinion after research of the scientific literature is that carbon dioxide (CO2) is not a major contributor to current global warming nor to Earth's paleoclimates.”
According to Leighton Steward, “In addition to being shown to not being a significant driver of current temperature change, CO2 is shown to be a positive factor in Earth's ecosystems, a benefit to the plant (food) kingdom and thus the animal kingdom, which includes humanity.” 
- Plants Need Co2 — President/Chair. 
- CO2 Is Green — Spokesman and Chair.
- Institute for the Study of Earth and Man (ISEM) — Chairman. 
- EOG Resources — Director. 
- American Petroleum Institute (API) — Honorary Director. 
- Louisiana Land and Exploration Company — Past President, Chief Operating Officer and, Chairman of the Board and Chief Executive Officer. 
- The Right Climate Stuff (TRCS) — [Pending further investigation]
- CO2 Coalition — Member, Board of Directors. 
According to a search of Google Scholar, Steward has not published any articles in peer-reviewed journals on any subject.
“REGISTER ENDORSERS FROM THE UNITED STATES OF AMERICA of The Climate Scientists' Register,” International Climate Science Coalition. Accessed May, 2012.
Josh Harkinson. “No. 4: Plants Need C02,” Mother Jones (Part of “The Dirty Dozen of Climate Change Denial series), December 4, 2009.
“Officers/Board,” eog resources. Accessed May 7, 2012.
“Recommended Reading List: 'Fire, Ice and Paradise', Steward, H.L. (2009),” Planes Need CO2. Accessed May , 2012. Archived May 7, 2012 with WebCite.
Paul Bedard. “Steward's 10 'Myths' About Global Warming and CO2 Damage,” Washington Whispers, October 9, 2009.
Anne C. Mulkern. “Ads Backed by Fossil-Fuel Interests Argue 'CO2 Is Green',” The New York Times, July 14, 2010.
“Speakers,” 4th International Conference on Climate Change, May 9 , 2010. Archived June 10, 2011.
2009 Form 990 for Plants Need CO2.org (PDF). Retrieved from foundationcenter.org.
“Institute Trustees,” Institute for the Study of Earth and Man. Accessed May 7, 2012.
Daniel F. Cuff. “BUSINESS PEOPLE; Louisiana Land Gives President 2 More Titles,” The New York Times, November 17, 1988.
“H. Leighton Steward,” SourceWatch.
“Return of Climate Denial-a-Palooza: Heartland Institute Hitches Anti-Science Wagon to Vegas FreedomFest,” DeSmogBlog, July 7, 2014. Archived July 14, 2014.
H. Leighton Steward. “Speakers,” At the Crossroads; Energy & Climate Policy Summit, Texas Public Policy Foundation, The Heritage Foundation, September 25/26, 2014.
“'The Hard Question™' Launches at National Press Club, The Conversation begins with 'Setting the Course on Energy'” (Press Release), Pr News Wire. January 21, 2013.
“NASA Retirees Appeal to their Own Lack of Climate Authority,” SkepticalScience. January 24, 2013.
“CO2isGreen.org: Team of Ex-NASA Scientists Concludes No Imminent Threat from Man-Made CO2” (Press Release), Pr Newswire. January 23, 2013.
“The Right Climate Stuff Team Releases New Report, Finds 'No Convincing Evidence Indicating Our Planet Is in a Climate Crisis',” The Heartland Institute. April 13, 2013.
Harold H. Doiron. “Bounding GHG Climate Sensitivity for Use in Regulatory Decisions,” February 2014. Retrieved from therightclimatestuff.com June 1, 2015.
H. Sterling Burnett. “Heartland Daily Podcast – H. Leighton Steward,” Somewhat Reasonable. January 12, 2015.
H. Leighton Steward. “Senators Should Know the Truth about Global Warming Leighton Steward,” TownHall.com. March 26, 2014.
“About,” Co2Coalition. Archived September 4, 2015.
“Background on Key Scientists Appearing in Climate Hustle,” Climate Hustle. Archived January 11, 2016.