Proving Climate Change
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. Science is now carried out within 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, where the paradigm is entirely rejected, and replaced with a new one.
Within the field of glacial geology, this occurred in the late Twentieth Century. 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. We now understand ice streams to achieve fast flow through sediment deformation and the base, possibly with some basal sliding.
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. 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. We must make observations of the past and present, analyse trends and identify anomalies. We must situate our hypotheses, research aims and objective, and research questions critically within the research programme; 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.
You can read more about Research Design here.
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.