Just keep in mind that commodities are generally even more volatile than stocks and real estate could behurt by rising interest rates so you might not want to invest more than a total of 10-20% of your portfolio in these areas.
Even if the treaty were to come into force without the United States (which is doubtful, because other countries are waiting for the United States to ratify so that it will pay the costs of implementation), the American chemical industry would notbehurt because it doesn't rely on imports from countries likely to be treaty parties.