Tol was a board member of the International Max Planck Research Schools on Earth System Modeling and Maritime Affairs and the European Forum on Integrated Environmental Assessment.
[11] He acknowledges that this level of taxation is too low to significantly discourage fossil fuel use but argues it would help to stimulate the development of fuel-saving technology and improve the competitiveness of renewable energy sources.
[13] In 2009, Tol published a controversial paper that combined data from several earlier studies, concluding that at least some amount of global warming could lead to economic gains.
[14] In 2014, he published an update, correcting missing minus signs that had turned economic costs into benefits and adding data overlooked before; the mistakes he attributed to "gremlins".
[18] Tol was a coordinating lead author for the IPCC Fifth Assessment Report Working Group II: Impacts, Adaptation and Vulnerability.
In 2008, Tol collaborated with Gary Yohe, Richard G. Richels, and Geoffrey Blanford to prepare the "Challenge Paper" on global warming which examined three approaches devised by Lomborg for tackling the issue.
Of the 30 policy alternatives that resulted, Lomborg's ranking procedure rated the 2 dealing with controlling emissions of greenhouse gases 29th and 30th in terms of cost effectiveness.
[22] He pointed out that the study "stops short of the most that can be supported on a cost benefit basis" and stated that "it does not seem reasonable" to rely solely on Tol's own FUND model when alternatives "reported in the peer-reviewed literature are also credible".