Wagging the Dog

Wagging the Dog

My piece that was published last week at The Conversation entitled, What would happen to the climate if we stopped emitting greenhouse gases today? has had more than 350K reads – most read science and technology article of the week. Last week in my WU blog, I provided some background material trying to make that piece a little more intuitive. In this blog, I will expand on a couple of ideas that came up in the conversation.

Ocean, Atmosphere and History: It is interesting to me how the paths we take frame our perceptions and establish our social structure and norms. What an arcane statement.

Meteorology and oceanography have been studied as parts of natural science for centuries. Paul Edward’s book A Vast Machine gives an excellent historical perspective. As population grew, as agriculture expanded, and as exploration, colonization and commerce became global, meteorology and oceanography took on more and more important roles in society. The studies moved out of the curiosity realm of a handful of natural scientists.

For a variety of reasons, meteorology evolved quickly in the early twentieth century. Perhaps the most compelling reason for the emergence of meteorology was the impact on people and society. When we think about impacts, we are first drawn to risks from extreme weather such as tornadoes, hurricanes and blizzards. However, there is a more, perhaps, benign aspect, where weather that is not extreme is used in planning. When to fly? When to plant? When to bet against Peyton Manning? Weather is important and it is consequential to people on a day-to-day basis.

The need for weather information in both peace and war brought motivated people to problems of forecasting. This led to the development of ways to measure the atmosphere. With the recognition that the atmosphere behaved as a fluid, there was development of the foundational theory of dynamical meteorology. Physical meteorology emerged as thermodynamics was applied to understand precipitation. As the observational and theory-based knowledge were conflated, it was realized that there was the potential to predict the weather. The emergence of digital computers greatly advanced predictive skill and the development of atmospheric models.

For many years, weather forecasting models did not even calculate the heating from the Sun and the cooling of the Earth to space. Their goal was to take an observed snapshot of the weather and to project that snapshot forward in time as long as possible. When started, practitioners of numerical weather prediction were excited when a day or two of skill was realized. The ocean? The ocean was largely absent in early models. Some years later it was recognized that sea surface temperatures might influence weather forecasts.

We have, here, the fact that predictive models developed from not only an atmosphere-centric point of view, but from a weather point of view. The development was framed by the limitations of computational and financial resources as well as by the expert judgment of what the scientists at the time thought was the most important thing to do next. The history and culture of weather forecasting had and have an enormous impact on climate science.

While weather-forecast science evolved with a compelling, societal purpose, physical oceanography and climatology remained more in the realm of the curiosity-driven. Though, no doubt, advocated and recognized as intellectually and societally important, these disciplines did not have the societal imperative. For example, though important to shipping, surface currents in the ocean are relatively slow changing relative to how long it takes a ship to move rubber ducks from Hong Kong to the U.S. Adequate knowledge of surface currents might, arguably, be obtained from mean measurements. As for climate science, original climate models were viewed more or less as a weather model, except that solar radiation was more important than weather.

Trying to explain the relation between the heat in the ocean and air temperature in What would happen to the climate if we stopped emitting greenhouse gases today? and my WU blog brought home to me the deficiencies of the atmospheric point of view. I have written about Point of View before and, specifically, that we are most interested in how climate affects us; therefore, we are most interested in the surface air temperature. Years ago, I understood that if I were to take a balanced look at climate science, then the role of the ocean was under appreciated, under observed, under represented and under communicated. (Same true for ice sheets.)

The discussion about the atmosphere and ocean put me in mind of the arguments about whether or not the Sun revolved around the Earth (geocentric) or the Earth revolved around the Sun (heliocentric). The intuition that the Sun revolved about the Earth follows from our point of view and that our point of view is in some way fundamental. Observing the motion of the Sun and the planets in the sky, it was possible to argue that the Sun revolved around the Earth, explaining planetary motion with occasional epicycles, circles within circles that explained why the planets moved backwards. Eventually this perspective collapsed under the scrutiny of observations and physics.

If we followed the energy, then the natural focus of climate science would be the oceans. In fact, when I first heard about global warming (in the 1960s), many scientists said global warming would not be a problem for humans because the oceans would harmlessly absorb the excess heat. The ocean was viewed as a big static heat sink – big carbon dioxide sink as well. But the ocean moves energy and carbon dioxide around. What goes in can come out. If the focus in climate science and climate-change communication was on the ocean, then the temperature variability of the atmosphere would be largely framed as a response to the ocean. Our current perspective, the one that I took in the Conversation piece, is a bit like the tail wagging the dog. It is not incorrect; however, it frames climate change in a way that renders some very fundamental aspects of climate change difficult to communicate.



Figure 1: The tail wagging the dog from sketchedout wordpress blog.