A Belief in Science

A BELIEF IN SCIENCE

If you value the information that comes from scientific investigation, then you believe that observations, development of ways to explain those observations, development of tests to stress those explanations, and the ability to predict the next set of observations is a way to extract knowledge. It's not the only way to develop knowledge. It is, however, a process, a belief system, that has at its core the idea of evaluation, testing, and validation. A theory that follows from scientific investigation is not simply conjecture or speculation; it is testable. Under the scrutiny of tests it is accepted, rejected, or refined.

This figure of temperature and carbon dioxide is from the Marian Koshland Science Museum.


Figure 1.From Marian Koshland Science Museum (more info): Variations of Northern Hemisphere Surface Temperature and Carbon Dioxide.



In this figure there are variations in the temperature field that are not present in the carbon dioxide field. Scientific rigor requires that we investigate this variability, and with some confidence we can attribute the variability prior to about 1800 to volcanic activity and changes in the sun. There is no doubt that the further back we go from the present time, the greater the uncertainty. We, today, have much better observations of temperature, of solar variability, of volcanic activity, of carbon dioxide; we have better measurements of every quantity. Does the fact that we have better measurements today devalue the knowledge from the past? Change it?

It has been accepted for almost 200 years that the greenhouse gases, water, methane, and carbon dioxide, warm the surface of the Earth (see "Spencer Weart's The Discovery of Global Warming" ). Without the greenhouse gases the Earth would be a frozen planet. Over the past half million years the Earth has bounced between ice ages and temperate periods. Carbon dioxide has varied between about 200 parts per million (ice age) and 280 parts per million (temperate). We have now raised the carbon dioxide to 380 parts per million, more than the difference between ice ages and temperate periods. Given the simple science of warming by greenhouse gases, logic suggests a comparable warming in the future. Is there any reason to believe that the Earth responds in some way to keep the surface a comfortable temperature for humans?

There are many remarkable lessons to draw from the picture I presented above. We, society, noticed the small temperature difference between, for example, 1000-1200 and 1600-1800. Our civil records, our history, are ripe with examples of societal impacts. We are sending carbon dioxide to record levels; temperature is following. We have the ability to document with unprecedented accuracy, and we are noticing. We have the ability to predict. We also know that global civilizations have never seen an Earth as warm as we see today--will see in the next hundred years--the next thousand years.

ricky