I think it is fair to say that, on the whole, the response of governments to the requests of scientists to make this or that change to policy have been ignored. Sure, plenty of people come out to make soundbites, but apart from token gestures little of this has translated into actual action. In developing countries, this is because they would rather have a growing economy (usually, sadly, reliant on using oil and gas as fuels) as opposed to a "green" one. In already-developed countries, such as the US, the oil lobbies are too powerful to be ignored for long, and so overall not nearly as much has changed as some in the green lobby would have liked. Perhaps this is a good thing, since some people in the green lobby also have a tendency to reject any reasonable alternative to fossil fuels as well. Wind turbines killing birds, tidal power wrecking marine ecosystems, and now Nuclear falling out of favour in a big way since the disaster at Fukushima (when one of the strongest earthquakes ever was too much for anyway obsolete technology).
With respect to the last 18 years of data, the figures are still in some dispute I believe but even if you accept the position that the average temperature has remained essentially flat since about 2000, that also means that most of the last 15-odd years are still the hottest on record -- and we are still pumping in record levels of greenhouse gases. If the temperature isn't rising accordingly then that suggests only that the system isn't as simple as a linear response. Which I don't expect anyone seriously thought anyway. Or, if they did, then they were being rather naive. It should be obvious that the Earth is too complex a system for the temperature-dependence of greenhouse gas emissions to be linear over arbitrary timescales.