That is easy as well.
1. Electing Democrats. Villainize the GOP for opposing it, create panic and worry over AGW, tell the sheeple that only electing Democrats will prevent DOOM.
2. Take control over people's lives, tell them what they can and cannot do or eat.
3. Taxes taxes taxes.
4. Damage oil and coal industries, promote "green" industries.
5. Appease major factions of the Democrat Party; environmentalists, Animal Activists, etc.
Mostly #1 and #2.
1) The GOP is villanizing itself for not admitting global warming ( even without the anthropogenic part). And while we are far from being at a life or death situation there are clear signs of warming: just try to take a look at the glaciers, also , sea level seems to have risen about 10 cm in the last 40 years or so. Again this is not an immediate threat, but something to keep an eye on.
2) I think that's unrelated to AWG, specially in the US, where there is a clear tendency to overeating: mostly everyone can get whatever food he likes, even if it is a receipe for early diabetes. The "doing" part is even less clear to me. What is it that the government doesn't allow you to do which is not a criminal activity ?
3) Taxes , yea , taxes are a pain in the ass. But the three bigest expenses are healthcare, defense and pensions, Both healthcare and defense can be optimized in many ways ( but discussing that would require a separate thread). Whatever grants or subsidies have been granted in renewables are not significant compared to healthcare and defense, so I find this argument weak.
4. Well, yes, they do get harmed , slightly , but so far the greatest harm has not come from green industry but from the Saudi kingdom. Many fracking companies are going south because of low oil prices, and the same goes for tar sands companies. You can't truly blame it on green industries.
I don't like nuclear very much , but if I had to choose between nuclear and tar sands or fracking , I would pick up nuclear.
5. That seems a legitimate motive to me, not a perverse agenda.