There is a seventh claim I should mention, one that is not strictly a matter of science, but tied directly to the case for action on AGW:
7) A rapidly warming planet is generally bad for most living things on that planet.
The effects of global warming vary tremendously from region to region and certainly the much greater resources available to people in the rich/developed/first world mean that the impacts will be much less serious for them. The simple idea here is to understand that most living beings are adapted (or evolved) to life in a particular set of circumstances. Changing those circumstances makes survival more difficult. Something like 1 billion people live on or with less than $1 per day. How much safety line do such people have to adapt to changes in their mode of survival? If the plants you used to eat don't grow, maybe there's some other food source that will grow, or maybe you can move somewhere to grow that plant again, but figuring this out takes time and money, which you don't have. Moving is going to be a big problem anyway because most of the best livable land is already occupied. Animals are even worse off because they have no capacity to understand the problem and consciously adapt. Evolution will be no help in a timespan anyone should consider useful, if thousands of species go extinct this century, evolution won't replace them for millions of years (Keynes' "long run" quip comes to mind here). Even for people in the rich world who can survive the extra floods and droughts, having much of the world warring for water or arable land isn't going to be good for the global economy, and it's pretty likely at least some of the violence will spill over into Europe and North America in the form of terrorism or fears of nuclear proliferation.
In fact, #7 remains true even if you still deny #4 (that humans are responsible for the warming). Even a "naturally" warming planet will have these effects, and if deniers were sincere, many of them would support measures to prepare for some of these effects. Where exactly are the majority of Bangladeshis going to go when the rising ocean floods their mostly sea-level country? Where are millions of people in South Asia going to get drinking water when the glaciers are too small to provide enough melt water to feed the rivers?
You do often find deniers who admit the planet is warming, but deny that humans are the cause, and yet I cannot recall them supporting harm alleviation measures. In fact, quite the reverse, one of the denial-sphere's most famous people is Bjorn Lomberg, who up until quite recently took the position that global warming was real, humans are the cause, but it wasn't worth solving, and other problems are more worthy of our attention. He, of course, remained in good standing among denialist circles despite his acceptance of the basic AGW science because he agreed with them on the most important issue for deniers: We must do nothing about it. This is all that is required by deniers. Whatever sophist path you take to that destination is fine, just ensure your end conclusion is "nothing needs to happen now or soon."