From rising flood risk in the UK to record-breaking heatwaves
across Australia, elevated greenhouse gases mean we're seeing
warmer and wetter extremes in our weather than a century ago, says
Dr Markus Donat.
Markus Donat researches extreme
weather at the Centre of Excellence for Climate System Science and
the Climate Change Research Centre at the University of New South
1. What type of weather events do you look at, and how
do you define "extreme"?
My work focuses on temperature and precipitation extremes. In
both cases, "extreme" means particularly high and particularly low
values, compared to the expected range in a given region.
That means we look at peak temperatures and heat waves, as well
as cold spells. For precipitation, "extreme" can mean unusually
heavy rainfall over a single day or over several consecutive days.
Unusually long periods without any rain are also a type of extreme
2. How do scientists measure extreme heat and rainfall
events? How good is the data?
We've been working on creating a global database of
observations, which means overcoming several big challenges. One
issue is data gaps. We have very good observational coverage in the
northern hemisphere and in Australia, for example, but large gaps
in Africa and South America. Sometimes data exists in written
archives, but has never been digitised.