In his new book on climate change (review to follow soonish), Tim Flannery speaks of a future where there are no more "acts of God" with regards to the weather. I know what he means, but I am not so sure he knows exactly what he means. In the insurance sense, an act of God is something that is beyond human control, i.e. a disaster that we can't do anything about. One might argue that Katrina falls into this category.
There are a few issues here. Firstly, it appears as if there are some very human factors involved in disasters like Katrina, pre and post event. Certainly there were difficulties with evacuations, and it could be that action could have been taken sooner before the hurricane struck. Many think that there was too long a delay afterwards. Certainly the fact that many people live near the coast is always going to be problematic with these sorts of events.
I wonder, however, how much of the idea that we are ever in control is just Enlightenment hubris? The author of the book of Job got it right when he has Job saying "who has wisdom to count the clouds?" (Jb 38.37), by which he meant - only God. We are certainly getting better at aspects of weather prediction, lead by advances in Numerical Weather Prediction (NWP) and the use of radar and related tools for Nowcasting. But weather modification research such as cloud seeding is ambiguous in its results - we don't control the weather.
However, the point Flannery is making is that anthropogenic climate change means that the Earth's climate system isn't running the way it would if we weren't here, or if we were still hunter gatherers. From 8000 years ago, we've been modifying climate via land clearing and agriculture (William Ruddiman's hypothesis in Plows, Plagues and Petroleum - review to be posted soon). Now we are doing so at an accelerating rate - only atmospheric aerosols and oceanic thermal are keeping us from seeing the full results. At some stage, we will really begin to see the full impact, and if India and China forge ahead with more coal power stations, it will grow worse still. This will mean that there will be weather disasters forced by us.
A recent meeting on the role of climate change in tropical cyclone (TC) occurrence and severity has declared that changes are inconclusive to date - although the debate continues. The reports major concern is global warming driven sea level rise, which makes coastal locations more prone to flooding and storm surge from TCs.
So, in a physical sense, Flannery is correct (with with regards to TCs). But is he correct in a metaphysical sense? Act of God is a nice insurance cop out, but theologically it is inconsistent to only blame God when things go wrong. If there is a god something like that proposed in the Judeo-Christian (or indeed Muslim) traditions, then there is a sense in which that g/God supervenes over all "natural" events. St Paul said that all things were held together in Jesus (Colossians 1.17), who is worshipped as God by Christians. In this sense, then nothing that occurs (including weather related disasters) is NOT an Act of God - though this raises issues of why these events are allowed to occur at all. More on this at another time. Yet, Paul also acknowledges that God gives people over to the consequences of their sins (Romans 1).
Pushing the climate system beyond its natural range (or at least that which is comfortable for us) means that we will suffer the consequences. Putting God into the picture means that we are allowed to suffer the consequences of the sins of greed and indifference to that which is a gift to us to look after. Whether you are a theist, deist, agnostic or atheist, it doesn't take much faith to realise that the future is uncertain and unpleasant unless we start acting now. Even then, much will be lost, and it will be the Act of People.