I think what's perhaps most worrying about the situation is that there could be a long-term significant warming trend that is perhaps 75% or more natural variability, and the AGW crowd may have mistaken the trend lines around the 1980s and 1990s which made it look as though this warming was largely human caused.
Getting near the end of a long analysis of temperature records for several long-term locations that I don't believe have changed their site characteristics, and seeing considerable evidence that a warming trend that was already unfolding in the time frame of 1910 to 1970 then stalled out and reversed for a while, hitting a minimum in the late 1970s and early 1980s (more like mid 1980s for Europe) then resumed back to former trend lines around 1988 to 1991. This is about when the AGW movement really began to take off.
The danger there would be (a) the warming is real but (b) the cause is natural and not human-induced, therefore the policies suggested by climate science will have almost no effect on it. This will have harmful economic consequences but will do next to nothing to resolve the problem.
We may have caught a break with the solar downturn if it digs in and becomes at least similar to the Dalton. I think getting it to go full Maunder is perhaps too unlikely, but even a Dalton style series of weak peaks and long pauses would perhaps slow down the natural warming.
One of the bigger pieces of evidence I've found for this alternative viewpoint is that warming seems to have locked into synchronized timing in different parts of the world. If there was a human signal, I don't see why that would necessarily be the case. I am also suspicious of the conventional theory because of the continued large natural variance of climate. If human warming was the main actor, wouldn't the variability be decreasing?
Is it therefore more of a crisis? Well that depends on what you think a natural warming cycle could eventually end up doing. We have had them going on ever since the end of the last glacial period -- sharp variations that have led to rises and falls in sea level much larger than what we saw in the past 120 years. We certainly need to be mindful that if the causes of warming were largely natural in the past century, then everything we are talking about and planning is irrelevant. The climate could continue to warm up anyway. Or it could reverse course.
I think it calls for an entirely different strategy, certainly careful monitoring and more research into predictable cause and effect, so we can have some clue what is coming at us, but also a shift away from prevention to mitigation. Prevention is only sensible if there is a good chance that it will prevent something. Mitigation is the more sensible choice if the outcome is inevitable. Looking at the resumed natural warming signals, I think the chances are fairly high that we'll continue to see warmer temperatures for several decades, although there's no telling when the natural signals will reverse.
Here are some interesting facts from a study of temperature records at Toronto, where the downtown station essentially hasn't changed its location or characteristics for many decades. There was an obvious warming trend there in the 1890s and a peak of warmth from 1911 to about 1960, followed by a more variable period, some slight cooling around 1980, then a steady warming but mainly due to the increased urban heat island as it's only overnight temperatures that have come up relative to 1931-60. In fact, 15 of the 20 warmest days observed at that location were in the interval from 1900 to 1970, and only four in the last half century (one other was in 1854). Throughout the year, the modern period has not produced any more records per annum than the years from 1911 to 1960 produced. 1931 and 1936 have more surviving record max values than any year since 2000 although some of the top ten years are recent. They have not eclipsed the pace set in other years, just returned to it. The "global warming" we have seen since 1990 would look exactly the same if time was reversed, to an observer who began looking in 1975. If the years came in reverse order, that observer going backwards would have already had seen nine of the twenty warmest days, going forward he has only seen four. Going backwards, he would have seen the two warmest Octobers, the second warmest July (and the warmest one would still lie ahead), and two of the three warmest Marches.
It is not scientifically possible to distinguish the warming observable in either direction from a mid-point such as 1975. Therefore I can't accept that the warming is a human caused phenomenon. We may be topping it up, but if you remove the urban heat island from the Toronto signal I can't even see that being valid.