Global climate change is the most significant environmental issue facing our nation and the world. There no longer is any question that global warming is occurring. Nor is there any serious debate about whether human activity is the root cause. If we fail to make significant reductions in greenhouse gas emissions over the next ten to twenty years, we face the possibility of catastrophic environmental harm by the end of this century.
Avi-Yonah, Reuven S. "Combating Global Climate Change: Why a Carbon Tax is a Better Response to Global Warming than Cap and Trade." D. M. Uhlmann, co-author. Stan. Envtl. L. J. 28, no. 1 (2009): 3-50.