Climate Modeling

If earth’s temperature is rising—no matter what the cause or causes—how will it affect us and the environment? Precise predictions are hard to make. Nowadays, though, scientists have access to powerful computers, which they use to create digital simulations of the climate system. Incorporated into their models are the laws of physics, climate data, and natural phenomena that influence climate.

Simulations enable scientists to experiment with climate in ways that are otherwise impossible. For instance, they can “change” solar output to see how this affects polar ice, air and sea temperatures, evaporation rates, atmospheric pressure, cloud formation, wind, and rainfall. They can “create” volcanic eruptions and examine the effects of volcanic dust on weather. And they can examine the effects of human population growth, deforestation, land use, changes in the emission of greenhouse gases, and so on. Scientists hope that their models will progressively become more accurate and reliable.

How precise are present models? Much, of course, depends on the accuracy of the data and the amount of it fed into the machines. Hence, climate projections vary from the mild to the catastrophic. Even so, says Science, “surprises could spring from the [natural] climate system.” And some already have, such as the unusually rapid rate of Arctic melting, which has amazed many climatologists. Still, even if policymakers had only a rough idea of the consequences of present action or inaction, they could make decisions today that might reduce problems tomorrow.

With that possibility in mind, the IPCC examined six different sets of computer-simulated scenarios—ranging from unrestricted greenhouse-gas production to business as usual to severe restraint—each producing different climatic and environmental results. In the light of the predictions, analysts urge a variety of measures. These include mandatory limits on fossil-fuel emissions, penalties for offenders, more nuclear power generation, and the introduction of more environmentally friendly technologies.