| Until the end of the 20th Century, most | | | | |
| scientists thought they understood the nature | | | | However, with their old ideas now challenged |
| of our climate system. As the very | | | | by these new theories, scientists began to |
| foundation of their science, geologists | | | | notice the evidence of abrupt changes in |
| cherished the "uniformitarian principle" that | | | | their data. Pollen records and improved |
| held that the fundamental forces that molded | | | | carbon dating techniques in the 1970's |
| the Earth's features and climate were | | | | depicted stable climate periods interrupted |
| gradual, natural, stable processes that did | | | | by radical discontinuities that took only one |
| not vary over time scales less than tens of | | | | or two centuries to totally change the |
| thousands of years. | | | | vegetation of a region. |
| | | | |
| This idea became central to their training | | | | Since then, evidence from other studies such |
| through a century of debate over natural | | | | as cores of glacial ice and ocean sediments, |
| catastrophes such as the biblical account of | | | | has continued to accumulate as methodologies |
| Noah's flood. The concept of catastrophic | | | | have been progressively refined. This has |
| climate change became 'tainted by | | | | further built justification for heroic |
| association' with creationist zealots seeking | | | | research, by intrepid teams braving hazardous |
| scientific backing for fundamentalist | | | | conditions on heaving oceans or bitter, high |
| interpretations of Bible passages. And so, | | | | altitude polar ice sheets, to win samples |
| such stories came to be considered as purely | | | | deep and distinct enough to provide an |
| supernatural events, with no place within the | | | | unambiguous picture of the Earth's geological |
| objectivity of science. | | | | and climatic past, a picture that shows that |
| | | | violent, spectacular short-term shifts were |
| Any evidence to the contrary...and there was, | | | | common. |
| in retrospect, plenty of it... was at first | | | | |
| readily dismissed. Sudden climate change in | | | | As a result, scientists en masse were |
| the Earth's past was blurred by imperfect | | | | beginning to entertain the possibility of |
| data and lack of refinement in early | | | | abrupt change, this new attitude reflected in |
| scientific methods. Where abrupt changes in | | | | a statement from the Intergovernmental Panel |
| the geological record were indisputable, | | | | on Climate Change in a 1996 report that |
| these were written off as regional | | | | concluded that 'climate surprises' were |
| curiosities, arising from purely local | | | | possible. The point was not emphasized at |
| impacts - such as a forest fire or the | | | | the time, and received little press |
| introduction of agriculture - impacts that | | | | attention. Many scientists also passively |
| had nothing to do with climate. | | | | rejected the facts by refusing to revise |
| | | | their accustomed ways of thinking about |
| Until dating methods were perfected, | | | | climate. |
| chronological correlation of data collected | | | | |
| at different locations around the globe was | | | | Not until 2000 did paired ice-cores, |
| not possible, and even when it was possible, | | | | extracted by competing teams in Greenland, |
| was not at first even pursued. Global | | | | match to show irrevocable proof of abrupt |
| changes in climate had different effects in | | | | climate shifts taking effect over mere |
| different areas, further complicating the | | | | decades (see R.B. Alley's book 'The Two-Mile |
| issue and obscuring the true scope of abrupt, | | | | Time Machine'). Similar cores were drilled |
| world-wide climate shifts. | | | | in Antarctica and revealed the global scale |
| | | | of the shifts. This forced the climate |
| In fact, the uniformitarian climate paradigm | | | | community to arrive at consensus. |
| was scarcely doubted until the 1950's when a | | | | |
| group of scientists set up a physical ocean | | | | Now respected climate scientists concur that |
| system model that demonstrated that | | | | the potential for fast climate change |
| circulation could flip rapidly from one | | | | evidently does exist, and could surprise |
| stable state to another. Scientists began to | | | | humanity with a climate shock within the |
| concede that change may only take thousands | | | | lifetimes of you and I. However, the new |
| of years. | | | | paradigm has not extended beyond |
| | | | geoscientists to the impacts community - |
| This view of the change-rate capacity of | | | | economists and other specialists are slow to |
| climate was reduced to mere hundreds of years | | | | turn their attention to the consequences of |
| in subsequent decades, beginning in the early | | | | climate change, and policy makers and the |
| 1960's when mathematical models that | | | | public are even more ignorant of the risks |
| incorporated climate feedback factors such as | | | | humanity faces. |
| snow and ice cover (albedo effects) suggested | | | | |
| that global climate really could change | | | | Because science has been late to wake up to |
| enormously in a relatively short time. | | | | climate change, crucial information about the |
| | | | potential behavior of our climate has only |
| In the mid 1960's deep sea sediment cores | | | | very recently come to light. Relentlessly |
| finally revealed that the planet had | | | | emerging climate surprises have thrown into |
| experienced several ice-age cycles of gradual | | | | painful relief just how inadequate our |
| glacial buildups over 90,000 year intervals, | | | | understanding of the climate system remains. |
| punctuated by more rapid 10,000 year | | | | Like a snowball rolling down a mountain, |
| de-glaciations. Because of the huge lag | | | | climate change is gathering momentum, racing |
| between global climate shifts and deep sea | | | | ahead of even the most pessimistic |
| temperature responses, even this data belied | | | | predictions. |
| the extreme magnitude of changes on the | | | | |
| surface oceans, land masses and atmosphere. | | | | Will you be ready? |