Luke warmism is the belief that the earth has been warming, but not dangerously so. In fact, global warming has been the single best thing to happen to humanity in the past 18,000 years.
I believe science demonstrates the following:
1) The earth has been warming since the end of the last ice age. We are in the middle of the Holocene Interglacial Period, which means that since the last ice age, the earth has been warming greatly on its own behalf...well before man started contributing.
2) The USGS states that sea levels have risen 410 feet since the last glacial maximum...again, the sea levels began rising well before homo sapiens started contributing in any meaningful way.
3) I'm sure man is contributing more now than man did in the past (when the warming began).
4) The global temperature cycle is cycles superimposed on cycles. The overall trend is warmer (which is what has allowed man to become the dominant species), but there are times when some downward temperature factors superimpose over one another, and you get short term drops in the overall warming cycle. We had a "Little Ice Age" a while back...google it. There may be periods where the Earth does not warm as much, but that doesn't mean the world isn't still warming. However, we seem to be near the mid point of the Holocene Interglacial Period, so in the next few thousand years, temperatures may begin to drop significantly.
There is a scientific consensus on all of the above.
I don't believe that there is a scientific consensus on the following:
a) Mankind's contribution to natural warming is likely to put us over the top, and prevent the next Ice Age. (This is a hypothesis, but it has not been proven by any means. This hypothesis predicts a stark departure from history, so the standard to accept it must be higher. History indicates the Earth will cool in the next few thousand years.)
b) Mankind's contribution to natural warming must be stopped in ways that redistribute wealth among nations in ways that match anti-colonial political movement. (This is a political view, not a scientific view.)
c) The US must enact measures in the next 5 years, or the world will end as we know it. (This alarmism is not justified, and is not a consensus among scientists.)
d) The US cannot wait to act until it is in a better financial position (less debt) to act. (Not a consensus.)
e) The world cannot wait to see what the effect is of running out of fossil fuels. (Not a consensus.)