Seelye Fellow, Professor Chris Budd OBE (University of Bath) provided a thoughtful and well-balanced public lecture earlier this week looking at whether climate change is occurring, and how mathematics can be used to understand some of the changes in climate we see today.
(Media-Newswire.com) - Seelye Fellow, Professor Chris Budd OBE ( University of Bath ) provided a thoughtful and well-balanced public lecture earlier this week looking at whether climate change is occurring, and how mathematics can be used to understand some of the changes in climate we see today.
The lecture attracted a significant amount of public interest, and so despite a rainy evening in Auckland City, over 200 people still made their way to campus to attend – which Chris was very pleased to see.
“I was delighted by how many people came along – especially considering the weather – and it was nice to have a mixed audience with people who supported both sides of the climate debate” says Chris.
“It was also great to see that the talk engaged them to take part in a very thoughtful and interesting discussion afterwards”.
Chris opened by looking at each of the five key indicators of climate change - increase in temperature, increase in extreme rainfall events ( such as the recent extensive flooding in the UK ), increase in carbon dioxide in the atmosphere, increase in sea level, and decrease in arctic ice – and discussing how each of these indicators have changed over the past several thousand years.
He took the audience through some of the general trends of climate change in the recent geological past, and demonstrated that the climate has had both warming and cooling periods, associated with changes in the total ice cover, with the most recent warming 10000 years ago at the end of the last ice age.
He said “If the climate were left to itself and followed its past natural trends then it is reasonable to expect that the temperature and carbon dioxide should now be starting to go down – but that’s not that case. Instead, we have a sudden and quite rapid rise in both temperature and carbon dioxide in the last 200 years. This strongly suggests that things have changed in the climate – and these changes appear to be man-made”
Chris then went on to discuss chaos theory, and its implications in the climate debate. Using the double pendulum to demonstrate the dynamics of chaos theory, he gave some insight into why climate and weather can be so difficult to predict and how even the smallest shift in initial conditions can have unpredictable consequences in the future
“Chaos occurs when, despite having a very well defined system that you can write equations for, the actual dynamics of the system are really hard to predict. Why? Because even the smallest change to the system can lead to complicated changes later on.” Chris explains.
“Weather is an example of this – where while we can predict with a reasonable level of certainty what the weather will be like tomorrow, it becomes increasingly difficult to predict what the weather will be like as we go further ahead in time. This is sometimes used as an argument against predicting the climate 100 years into the future. However, predicting climate is mainly about identifying general trends, rather than day to day variations, and this can be done with more certainty.
That is how mathematics can be used, and why it is useful for understanding the shifts in climate behaviour. Mathematicians work with climate scientists to understand ( and predict ) climate patterns using equations which allow you to assess the impact of different factors upon the climate.
The difficulty however is that because climate behaviour is affected by so many different factors, the equations and models used to predict future behaviour are incredibly complex and can be prone to mistakes. This is why mathematicians are working to come up with simpler models that are easier to use and provide some insight into what is happening and can be used to verify the more complex ones.
The question now though is whether the changes we are seeing in climate behaviour are simply part of the natural trend ( with some man-made anomalies ) – or if the worrying rate in which the temperatures are rising and the arctic ice is decreasing will continue so that by 2100 all of the arctic ice will have irreversibly disappeared.
The mathematical models are very useful in this respect as they have no inbuilt bias and show, unambiguously, that the large recent man made increases in carbon dioxide ( and other greenhouse gases ) in the atmosphere, must inevitably lead to an increase in the global temperature and a reduction in the ice. He demonstrated this through a simple mathematical formula for energy balance, that he disucssed in detail with the audience.
Chris has one more week in Auckland before heading off with his wife and son to explore New Zealand
“It’s been great visiting New Zealand, and I’ve been especially lucky to be able to bring my wife and son with me.” says Chris.
“It’s also been great to be able to share my research with such a diverse range of people while I’ve been in Auckland - from the general public to fellow mathematicians here in the Department of Mathematics. I’m also giving a talk next week to the Science Scholars students here at the University, and will be doing a small schools tour in Palmerston North”.
The Seelye Fellowship was first established in 2006, and aims to attract distinguished academics who are leaders in their field to the University of Auckland for a short period of time where they can share their research and expertise.
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