Monday, August 01, 2016

Modeling Climate Change

For those who still think climate science and the scientific likelihoods for Climate Change are the stuff of dreams, they should focus for a while on climate modeling. Climate modeling (“quantitative methods to simulate the interactions of the important drivers of climate, including atmosphere, oceans, land surface and ice” Wikipedia) is anchored deeply in the laws of physics, math, and all the accumulated data on weather and climate from around the world. Predicting climate has come a long way as the software and hardware of computing have advanced quickly, making it possible for climate scientists to assert, with a high degree of certainty, that global warming is upon us and Climate Change is a grave threat.

Here’s a more rigorous argument from climate modelers:

 “In the face of criticism of climate science, it is important to note that the physical science behind climate models and energy is based on physical laws known for several hundred years and is not new or subject to question. If the world did not work this way, cars would not run, airplanes would not fly, and everyday motions that we observe (baseball pitches, gravity) would not happen. As we demonstrate later, these underlying scientific principles are not cutting-edge science. The principles are not open to question or debate, any more than the law of gravity can be debated.” (Page 39, 2016) Demystifying Climate Models, A Users Guide to Earth System Models)

Scientists can factor in the energy from the sun and follow it through many of our planet’s systems, including ocean currents, our atmosphere, and even model energy as it passes through plant and animal life. Unlike economics (where, if you run out of money you just make more), there are strict energy conservation laws to which climate models have to adhere. If you follow the sun’s energy through one of the many systems in a climate model and the numbers don’t add up, you have to find the missing or additional energy.

With the new climate models, scientists can even factor in many of humanity’s influences on our climate—beyond the production of greenhouse gas emissions -- which our way of life releases.

“Changing water availability affects industry and also affects agriculture. Agricultural land (pasture and cropland) has very different surface properties than natural vegetation, which can result in significant differences in evapotranspiration, affecting precipitation, and albedo, affecting surface temperature. Changes in precipitation and temperature in turn feedback on crops: requiring changes to crop types or additional irrigation water if available. All of these feedbacks can be predicted and modeled, with varying degrees of fidelity.”(Page 130, ibid) 

The take home message is that the more climate scientists learn about global warming (a subset of Climate Change) and gather information for climate models, the more certain they are that we are heading for disaster.

Climate models are accurately predicting ocean and global warming A new study from my colleagues and I vindicates climate models, which are accurately predicting the rate of ocean heat accumulation For those of us who are concerned about global warming, two of the most critical questions we ask are, “how fast is the Earth warming?” and “how much will it warm in the future?”. The first question can be answered in a number of ways. For instance, we can actually measure the rate of energy increase in the Earth’s system (primarily through measuring changing ocean temperatures). Alternatively, we can measure changes in the net inflow of heat at the top of the atmosphere using satellites. We can also measure the rate of sea-level rise to get an estimate of the warming rate. (July 27, 2016) The Guardian

Someday perhaps we may be able to factor in many other features of modern life that are affected by and effect climate, like how our cities take in and release energy.

There are limits to climate modeling. If we don’t include all the data we need to know in order to understand how our climate works (like monitoring clouds’ effect on climate), our models will be limited. Already, climate modelers are learning that their knowledge about clouds and climate is severely limited:

“Perhaps most chillingly, the study reveals how inadequate our present observing systems still are when it comes to certain fundamental climate questions—such as whether the world is getting more or less cloudy, Stevens adds. “This work reminds us that if we really want to understand our changing climate … we need to do a much, much better job of watching clouds.”” (Cloud patterns are shifting skyward and poleward, adding to global warming; July 11, 2016, Science Magazine)

More importantly, there are a lot of unknown unknowns (things we don’t even know we don’t know) that come with something so incredibly complicated as our climate. For example, a climate model won’t ever be able to tell us how our climate will respond to the human peculiarity called climate denial—a refusal to accept science and reason. If we react to every indication that energy is being trapped in our climate system with hostility and distain towards climate modeling, we will be stumbling about blindly on a very warm world.

Time passes.

No comments: