An Introduction to the Science of Climate Change
What is often meant by ‘climate change’, however, is the changes - and potential changes - in climate that are known to be induced by human activity (so-called ‘Anthropogenic’ changes). Like natural climate change mechanisms, the mechanisms of anthropogenic change are also many and varied but chief among them is the increase of the gas Carbon Dioxide (CO2) in the atmosphere that arises when fossil fuels (coal, oil and gas) are burnt.
Mathematical models actually do a very good job predicting climate changes over long periods. The models incorporate laws of physics with climate variables such as land, sea and ice. The more sophiisticaetd ones include land vegetation, sulphate and non-sulphate particles suspended in the atmosphere. Then models are run using different scenarios from which climate change affects are deduced. Of course there are errors. The model is not an exact replication of actuality and the goverening set of equations is incomplete. Setting the right parameters so that variations are missed or the one hand or so so detailed onthe other that trends are ignored. Finally, you can never be sure that was has happened in the past is going to predict a future state. Bias and other limitations can also reduce the effectiveness of the model.
We can also never be sure what one variable will have on an other. Will it be a negative of positive feedback. For instance the laoding of more greenhouse gases in to the atmosphere will lead to global warming. But this could be offset by another variable to negates the expected increase in temperature. Alternatively, the other varible may help to speed up the global warming even more quickly.
Running a range of models can tell us about our aleatoric normal chaotic nature of climate change and epistemic uncertainty, that is, the extent the system is loaded with a different mix of variables to give us a possible range of outcomes.
Local Climate Changes
Overall global climate changes are unlikely to affect all regions uniformally. One set of modeling scenarios may be predict drought for one region but the same scenarios may predict floods for another. And it makes predicting climate changes for all regions of the planet that much more difficult.
Employing a chain of numerical models can help us understand the full impact of athropogenic influences such as
- Emissions of CO2
- Concentrations of C02, Methane, etc
- Global Climate change - See levels etc
- Regional Variations - Mountains, tropical, etc
- Impacts - Food, water
