Developed countries only
It will be easier to come to an agreement with developed countries only, but the developing world will massively contribute to climate change in the long run, if left unaccounted for.
As the president of the United States crafting national and international strategies for dealing with climate change, you have made a series of decisions. Let's analyze the implications of each of your choices.
First, you decided to simply announce a new set of carbon emissions goals instead of advocating for concrete policy change. This decision will not help the US combat climate change as the goals you have set are unenforceable. Lobbyists, NGOs, scientists, and the international community are sick of toothless political statements and view your attempt at domestic leadership on climate change as a failure.
Second, you chose to engage with developed countries around the world in order to craft a comprehensive agreement on climate change. As a coalition, the countries involved agreed to share technology and set binding emissions standards. Collectively, the developed world will do its part to ensure the world does not reach the two degree Celsius tipping point that climate change scientists warn about. However, you must keep in mind that developing countries will control the future of climate change.
Overall, you have done a fair job. You did not make any meaningful progress with regards to domestic energy policy. That being said, you crafted a solid agreement with the developed world to ramp up its climate change response. Hopefully, your efforts will result in cooperation with developing countries later on.