Thanks for your comment, Amelia. To clarify the graph in the article, both CDLI companies (those that measure and disclose their carbon emissions well) and CPLI companies (those that reduce carbon emissions well) delivered twice the financial return compared to their peers.
The CPLI companies, especially, are already leaders in carbon mitigation. Rather than being dragged behind in financial performance for going green, as is commonly believed, they delivered 2x financial return compared to their peers! So they are both green leaders and financial leaders.
One can draw various explanations on why this is the case, but it's hard to argue going green drags down a company.