Any country's positive actions regarding mitigation - to any degree - can reduce anthropogenic climate change, which is undeniably good. Whether other countries follow suit is irrelevant, especially if doing so makes it easier for others to later. America is a huge contributor to green house gas production and the question itself doesn't ask if TPP is enough but if that of the entire country is.
While I do believe it is important to do all that we can to protect and conserve the environment, there are far bigger contributors to climate change than the US, so merely enacting national laws and initiatives for environmental protection will not make a significant impact to combating climate change. Until countries such as China and India begin to put similar environmental protection laws into effect, little change will be seen.
Under the TPP, corporate polluters will be able to sue the United States when they don’t get what they want. Corporations are already doing everything they can to buy influence in our democracy and use their dollars to drown out the voice of the people — the last thing they need is more influence over government.
While I think the US laws are a great start, hardly anything can be done to reverse or less the worsening of climate change unless the rest of the world hops on and agrees to take actions to lessen their environmental footprint. Imagine a world where 60% was able to completely stop using greenhouse gas emissions. But the other 40% ignore the request, and even created worse gases. Was this change really worth it in the end?
The United States actions on environmental change means nothing in the big picture. Hardly any other countries will follow suit because our policies are generally toothless. Maybe if we enforced the laws that are already on the books other countries would take us more seriously when we proclaim things to others