They say that 97% of scientists agree that the world has warmed.
Using the bottom of the Little Ice Age until now,it is surprising that 3% didn't agree that the world had warmed.
The question asked by Doran, and Zimmerman (2009), Examining the Scientific Consensus on Climate Change, Eos Trans. AGU, 90(3) was "When compared with pre-1800s levels, do you think that mean global temperatures have generally risen, fallen, or remained relatively constant?"
However the 97% was derived from a flawed study. See Here, here, here and here.
What if the sceptics start claiming the consensus?
Well, as the sceptical side of the debate is science based, you won't hear sceptics claiming a consensus. Consensus is a political term, not a scientific term.
Having said that, James Taylor in Forbes.com uses the "C" word. (link)
It is becoming clear that not only do many scientists dispute the asserted global warming crisis, but these skeptical scientists may indeed form a scientific consensus.
Don’t look now, but maybe a scientific consensus exists concerning global warming after all. Only 36 percent of geoscientists and engineers believe that humans are creating a global warming crisis, according to a survey reported in the peer-reviewed Organization Studies.
By contrast, a strong majority of the 1,077 respondents believe that nature is the primary cause of recent global warming and/or that future global warming will not be a very serious problem.James previously reported that (link)
Only one in four American Meteorological Society broadcast meteorologists agrees with United Nations’ claims that humans are primarily responsible for recent global warming, a survey published in the Bulletin of the American Meteorological Society reports.
As the late Israeli diplomat and politician Abba Eban said: "A consensus means that everyone agrees to say collectively what no one believes individually. "