Prioritize...
After completing this section, you should be able to:
- Define the term "model" in a scientific context.
- Describe, in basic terms, what a climate model's purpose is.
Read...
"It's tough to make predictions, especially about the future." This Danish "proverb" (often attributed to the baseball great, Yogi Berra) is especially apt now! Last lesson, we focused on how the climate has changed when we look backward. Past trends in air temperature and their consequences for ice coverage, sea level rise, atmospheric moisture, extreme weather, etc., are things that scientists have already observed. But what does the future hold? How will climate change impact us in 10 years? In 100 years? Answering those questions is challenging for scientists because of all the variables involved in predicting the future. In an ideal world, scientists could use some sort of identical planet, just like Earth, to compare observed changes to our climate to those without human influence on the identical planet. Kind of like a placebo. But no such planet exists! Therefore, scientists are forced to use the next best thing – a climate model.
First, let’s understand what a model is. In absolutely the most basic terms, a model is a simplified representation of a real-world system that helps us understand, explain, predict, or manage processes. Models can be physical objects, such as scale models of buildings or rockets, or abstract constructs, like mathematical equations and computer simulations.
Now, when it comes to science, models are often used to simulate complex systems by incorporating various different variables and how they interact with one another. By simplifying the real world, models allow scientists to experiment with different scenarios, make predictions, and explore outcomes of various changes in the system being studied. For example, in epidemiology, doctors build models to simulate the spread of infectious diseases. They may have variables like population density, temperature, whether people are locked down, etc. This helps researchers predict outbreak patterns, assess the effectiveness of interventions like vaccination, and plan public health responses.
At its core, that is also what a climate model does! It’s impossible to track every molecule in the Earth’s system at any given time. However, we can use what we have learned in this class to simplify the system and then use computers to predict what the future climate might look like. We can do things like add extra carbon dioxide to the atmosphere or remove aerosol pollution and see what happens... all without having to wait 100 years to find out!
There is a range of types of climate models, each varying in complexity and scope. When you hear the term “climate model” in some news article or even on TikTok, you should remember that it isn’t a one-size-fits-all term. For example, we can have "toy" models. These (very) simple climate models focus on basic processes and provide a broad overview of what is going on in the Earth’s climate system with minimal (or no!) need to use a computer. They often use basic concepts, such as the balance between incoming solar radiation and outgoing infrared radiation, to estimate changes in global temperature. They are simple enough that you can write them out with a pencil and paper.
Remember when we talked about the Earth’s equilibrium temperature in the context of radiation? Energy in = energy out? True story: we were actually “building a model!” Simple, yes, but useful for understanding how the climate system behaves!
