Originally posted by: BryanLeyland
But, the most important thing is that the world has not warmed in the last 16 years and that this proves that carbon dioxide does not cause dangerous global warming. People who study sunspot cycles are predicting that the world is about to enter - or has entered - a cooling cycle. History tells us that warming is good and cooling is bad. History is more valuable than computer models that have produced a long series of failed predictions.
The climate is extremely complicated, I am not sure anyone has proved their case.
On short timescales heat flows and temperature changes may not correlate in simple ways. Some simple examples highlight why we should be wary of rushing to premature conclusions on this topic.
1. If I apply a bunsen burner to a glass of water filled with ice cubes the temperature of the glass will not rise until all the ice is melted. How much net ice being melted needs to be factored into your calculations. Latent heat of melting/freezing
2. The thermal capacity of the atmosphere is low compared to water. Therefore the same amount of heat will raise the temperature of air more than the temperature of water. How much excess heat in the atmosphere will ultimately be being mixed into the deep ocean? I am not sure anyone knows this; any significant mixing will reduce the rate of atmospheric temperature increase for a given heat input.
3. The problem of vertical convection and the lack of experimental data on this.
4. The problem of water evaporation from the oceans and land into the atmosphere, and recondensation in the atmosphere. What are the heat flows here, and how much of this gets radiated away in the high atmosphere.
5. The problem of the radiative effects of clouds. The subject of my unwritten up PhD.
6. The problem of developing regional climate change models that will be of more use to political decision making than a single global temperature average output. Even if global temperatures rise in future years the temperature in the UK northern european region may decline on average.
How will climate change affect us in future? What are the consequences for society if our climate predictions prove wrong?
There are other climate change effects that could happen: What would be the effect of a seriously big volcanic eruption in Iceland? Have we enough food to go around if there are two or three very severely cold years in the northern europe following an eruption?
It is because we are uncertain about what will happen next, that (systems) engineers should be involved in helping policians to make decisions.
Remember, changes in the spatial distribution of precipitation produce hardship for societies on much shorter timescales than changes in the spatial distribution of ambient temperatures. It is important that we develop and improve climate models; even just being able to predict rainfall distibutions a few months in advance would be a massive boon. Climate scientists could flag up to politicians if there is a higher than normal chance of widespread crop failures, and help save lives.
If you are interested in these topics, you will need to use your knowledge of engineering principles to think through issues to a much deeper level than the general media can supply.