Climate scientist Dr. Simon Clark criticized it based on his fear of the self-licensing effect, which states that one's positive moral action makes them tend to worry less about future negative moral actions. As applied to Team Trees, Clark mentioned that someone who donates to the fundraiser may feel justified to perform other actions that might completely offset the carbon reduction obtained by planting the trees. As an example, he mentions how the carbon reductions from an entire lifetime of 20 trees could also be achieved by going vegan for six years, or could be completely negated by taking only four round-trip flights from western Europe to the western coast of the United States.