I was going to write about sea level and climate change, but have decided that this massive and complicated topic has already been covered in much more detail and has been much better written. I couldn’t possibly compete. However, when reading the New Scientists’ focus on Climate Change, I was struck by the number of comments along the lines of, ‘This is theory, we won’t believe it until you prove it’. Two things came to my attention. Firstly, that climate change has been accorded almost myth or religious-like status, and has become something that you can either ‘believe’ or ‘disbelieve’. Secondly, that many people are profoundly naive about the way in which science works. And so I was motivated to write a brief piece about scientific research design. Stay with me now – I’ll make it as interesting as possible!
The process of refutation
Early scientists thought that the best way to come up with a ‘unifying scientific law’ was through empirical observation. This is inductive research. Scientists carefully made observations of natural occurrences, and then formulated a law about their form / genesis / process etc. However, in the 20th Century, Karl Popper argued that science could only move forwards through a process of refutation. The classical example is this: a scientist goes to a lake, and counts the number of swans. He notes their colour, characteristics, behaviour, etc. He goes to the lake every day for a year, and at the end, proposes the law that all swans are white. Popper points out this is flawed; for to state that all swans are white, you must see all swans, everywhere, that ever existed. You only need to see one black swan to disprove this theory. Scientists should instead propose hypotheses, and then seek to disprove them. Scientists must always be critical. This is deductive, critical approach is fundamental to modern science.
As science matured throughout the twentieth century, this approach was gradually seen as inadequate. Under Popperism, the scientist is forced to always reject the entire hypothesis, and this does not bring the theory any closer to the truth. Thomas Kuhn in the 1960s proposed the concept of a paradigm or research programme. A paradigm has a fundamental core of hypotheses that are regarded as scientists as the truth, or as close to the truth as possible. This core is surrounded by an outer ring of auxiliary hypotheses, that are constantly being tested, updated and revised. Over time, these auxiliary hypotheses may call into question or threaten the paradigm’s core hypotheses, and may lead to a paradigm shift, a revolution, where the paradigm is entirely rejected, and replaced with a new one. The core hypotheses form a series of assumptions that a scientist makes when designing a piece of research, and this allows him to reject only the part of the hypothesis that is flawed. By continually testing and revising the auxiliary hypotheses, science either moves ever closer to the truth, or the assumptions are revised or rejected.
Within the field of glacial geology, a paradigm shift occurred in the 1990s. Up until this point, it was thought that most ice movement within fast-flowing ice streams was due to internal deformation of the ice, with possibly some lubrication of water at the ice bed inducing basal sliding. However, geophysical surveys and boreholes drilled though the Siple Coast ice streams in Antarctica indicated highly saturated sediment at the base of the ice stream, where most of the forward momentum occurs through subglacial deformation. We now understand ice streams to achieve fast flow through sediment deformation and the base, possibly with some basal sliding. Subglacial deformation is now a 'hot topic' in Quaternary Geology.
Siple Coast Ice Streams.
Other classic examples of paradigm shifts include flat earth / round earth, and whether geological formations of Britain were deposited by a Great Flood (Catastrophism) or by ongoing geological actions (Uniformitarianism).
Designing experiments to test climate change
Of course, this all can work very nicely if we have a simple little system, can we can easily create hypotheses, test them, and make conclusions. An example of this could involve pendulums. You can assume, based on previous research, that a weight on the end of a string will swing in a consistent manner. You want to find out whether the period of the pendulum swing is based on the amplitude - how far the pendulum swings. You hypothesise that if you start the pendulum swinging from twice as far away, the pendulum swing will take twice as long. You can set up a series of experiments to test, observe and time pendulum swings, and then evaluate whether your hypothesis is refuted or upheld. The key point is that the hypothesis is testable.
Unfortunately, the atmosphere, the oceans, and the ice sheets form a huge, interconnected system with numerous complex feedbacks. We cannot perturb this system to observe what happens. It is therefore necessary to conduct a measure of critical inductive research. The term 'critical' means that we still create testable hypotheses. We must make observations of the past and present, analyse trends and identify anomalies. We must situate our hypotheses, research aims and objectives, and research questions critically within the research programme and we must be aware of the paradigm within which we operate. Only then can we conduct relevant and useful research whilst still respecting Popperian ideals.
Who’s the climate sceptic now?
The way in which scientists are fundamentally trained from the start of their careers induces a highly sceptical attitude. Scientists are always trying to disprove their own theories. And because a theory can never be proven, climate change will remain a theory. However, it is important to note that over the last few years, the paradigm of climate change has evolved. Most scientists now accept the ‘hard core’ hypotheses as close to the truth. These core hypotheses state that the climate is changing, that atmospheric CO2 emissions are rapidly rising, and are now above any atmospheric CO2 within the last 600,000 years. Most scientists will accept the retreat of Alpine glaciers, rising sea level and rising temperatures. Surrounding this core is a more flexible belt, with hypotheses regarding the proportion of human intervention in the climate. And around the edge, hypotheses regarding the rate of change, comparisons to past change, and likely future change and sea level rise are regularly tested and updated. Scientists are the ultimate climate sceptics, who seek only to provide the best data possible, and who are always critical of their own and other’s work.
Climate change isn’t something one should or could ‘believe’ in or blindly accept; it is something we should constantly challenge. But we must make informed decisions. It is very important not to just take sides without reading all the arguments.
No comments:
Post a Comment