STOP! This is a 2013 paper. It is 2019.
Climate change is supported by evidence and we humans are the cause. The situation is worse than we ever imagined. It is an existential crisis, which must be mitigated. If we don't do something major and do it soon, extinction of much of life on earth will be the result. In fact, we may already be too late to be able to take actions to avert collapse.
Climate deniers are irresponsible, distracting, and amoral. They don't seem to understand how science is done and how scientific knowledge is created. They are well funded, apparently by the same cabal of folks that protected tobacco companies and blessed clean coal.
It is true that Global Climate and its various drivers is not well understood, yet we persist in under-funding research. We have too little data, too few people working on the problem, and no organization with global reach and global authority coordinating things, setting rules, and running things. Decisions about mitigation need to be based on rational analysis and not on political, economic, or social grounds. Some decisions and actions will necessarily be unpopular.
I too like what Eric Weinstein said about climate change:
">The fact that we do not have much historical data and good verifiable models to understand how the planet climate behaves under large changes in parameters (CO2 emission, etc.) makes it even more important and urgent to act. We never know at what moment the system will cross the threshold, and damage becomes irreversible, and planet destruction accelerates."
We are already in regimes which are outside historical experience and data, that is, in uncharted territory.
Personally, I think it may all be over and that everything will collapse sometime between 2030 and 2050 while everyone is sitting around denying that there is any problem.