The correct answer to this open question is the following.
The executive branch and bureaucratic agencies that might be involved in the work to combat climate change are the following.
The actual US federal government has a different approach regarding climate change, compared to Trump's administration. The present administration is committed to again be a leader in the combat against climate change.
The executive branch departments and agencies that participate in this effort are the Department of Energy, the Department of Health and Human Services, the Environmental Protection Agency, the Department of Agriculture, the Department of Defense, the Department of Commerce, the Department of Transportation, the Department of Transportation, the Department of Interior, the Department of State, the US Agency for Internal Development, the National Aeronautics and Space Administration, and the National Science Foundation.
Second, explain how climate change might constitute a collective action problem.
This is a major problem to be the concern of, not only by the federal and state governments but for every single citizen that has to be conscious that its actions impact the weather and the environment. It has been difficult to encourage individuals to fulfill the social responsibility of this type. And the reason why is that citizens think that they cannot do anything or that the problem is not theirs, it is the government and industries problem. Citizens do not value the direct impact and consequences of climate change until a Hurricane strikes their cities or after Earquake, or a tornado. Until farmers have not eh¿nough rain to grow their crops.