 I work with corals and using the stable oxygen isotopes to figure out what the temperature was 200 years ago 400 years ago and even the last thousand years so to do this we come up with a time series of oxygen isotopes and convert that into temperature and rainfall and I could tell you about how climate oscillations or climate variability changed over the last thousand years. I particularly look at rainfall in the tropics and the tropical rainfall belt or the inter-tropical convergence zone. So this is part of a large global circulation and we're trying to work out how it's changed over the last 400 years and how that is likely to feed into future climate changes as well. So the corals are telling us that a rainfall has changed quite dramatically especially in the last 100 years who's in the last hundred years who's seen that rainfall especially in northern Australia and southwestern Australia has changed dramatically. Northern Australia is getting a lot more rainfall and southwestern Australia is getting a lot less rainfall and using the corals we're trying to track whether this is going to change significantly again or whether there's it's part of a natural variability. We with a number of other paleo climatologists look at a pick up lots of different coral records so there's coral records all across the globe so we have a really nice spatial vision of what the coral what coral is telling us over the last 400 years or so and we can use this to map what the temperature is doing over that period and it gives us a better baseline of natural variability in the system.