It's worth reading this article from the American Institute of Physics on "The Discovery of Rapid Climate Change." The article describes how climatologists slowly became aware, over a period of more than 50 years, that climate could change not in tens of thousands of years, but in less than a decade.
The change did not come in a single flash of insight. Instead, it evolved slowly from an increasing weight of evidence and theory. But even the accumulation of evidence is not the whole story. Evidence for rapid change had existed all along, but was easily dismissed as flukes or noise, and sometimes even labeled crackpot. The shift in expectation had to go through several stages: no one would look for century-scale changes until thousand-year changes had been accepted as plausible.
As the article points out, the experiment that showed large-scale change in less than a decade -- the Greenland ice cores, reported in 1993 -- would never have been carried out if scientists hadn't already suspected that they needed to look for evidence of rapid change. And if those cores had existed earlier, scientists might well have analyzed them in chunks too large to spot any change faster than centuries. In fact, this had happened with sediment cores analyzed in ten-centimeter chunks.
The same pattern can be seen in molecular manufacturing. Despite Feynman's predictions more than 45 years ago, and evidence accumulted over the past 25 years, many scientists have refused to accept that nanoscale machines can be engineered, constructed, and used productively. The shift is coming gradually.
First, scientists had to accept that the nanoscale could be engineered at all. Then they had to build a few structures and play with microscopes before they would accept that atoms in covalent solids would stay where you put them. Then they had to study biological systems in detail before they could admit that integration of active components might be useful. Today, some scientists are actually building nanoscale and molecular motors and bearings, and a few are even talking about mechanical nanoscale manufacturing systems that transport and use individual molecules.
(If I have made scientists sound stupid in the previous paragraph, I do not apologize. For several decades, it was common to see mainstream scientific publications include quotes from scientists stating that "entropy" or similar considerations would make Drexler-style machines "impossible." These statements were never scientifically grounded, and were simply bad science. As the fashion in nanoscience shifts toward active nanodevices, we should not forget that many nanoscientists actively opposed the move only a few years ago. We should also keep in mind that nanoscience still has a ways to go before nanofactories and their products are widely accepted as goals.)
The funds required for those heroic projects became available only after scientists reported that climate could change in damaging ways on a time scale meaningful to governments. In an area as difficult as climate science, in which all is complex and befogged, it takes a while to see what one is not prepared to look for.Chris Phoenix