The Perse School

Confronting our Future – a lecture on climate change by Professor Chris Rapley

15 Oct 2015

Prof RapleyProfessor Chris Rapley, Professor of Climate Science at UCL and former Director of the London Science Museum and of the British Antarctic Survey, took to the stage with a challenge for the audience. Here, at the first in a series of lectures to celebrate four centuries of Perse history, we were asked to look forward 400 years to a radically different climate and geological era, called the ‘Anthropocene’. “Humans have always impacted the planet, one way or another, but now we are impacting the basic operating of the planet: its metabolism, its ability to lose heat into space. You don’t have to be a scientist to figure out that that might not be a wise thing to do.”

Rapley’s lecture provided a clear digest of the complex data that forms the evidence base for climate change. This very complexity is part of its fascination for scientists. As he explained, “The satellite era has opened up completely new ways of seeing the Earth as an integrated system – the most complex system that we’re aware of. The atmosphere, oceans, biology, people and technology all interact with each other in a myriad different ways. The physics, the chemistry, the geology, the ecology, the biology, the psychology, the economics all interact.” If you disturb one part of the system it can cascade throughout in a multitude of ways. Hence it is very difficult to predict the exact consequences of climate change.

The graphs and data he presented illustrated the complexity and the unpredictable consequences. A particularly striking diagram set current levels of carbon dioxide into nearly a million years of context (slide 3 on the slide deck). Drilling deep into the Antarctic ice offers scientists the ability to go back in time, to access 800,000 years of evidence about the atmosphere, laid down year by year, snowfall by snowfall. By extracting the ice cores, and then the air bubbles trapped within in, scientists can analyse the composition of past atmospheres.

What does this tell us? That ice age cycles correlate with changing levels of carbon dioxide and methane. There are natural variations and cycles triggered by astronomical events, volcanic activity and slight changes in the Earth’s orbit and tilt. For the best part of a million years the planet has been going through the same motions, oscillating through two extremes, until the last 100 years. The level of carbon dioxide in the last 100 years has not been experienced for several millions of years. The rate of change is over 100 times faster than anything seen in the natural cycle.  Rapley drove home the point: “We are the first humans ever to breathe air with 400 parts per million carbon dioxide. It is unprecedented in the human record and indeed in the recent geological record. This shock has hit the system and the repercussions are still playing out.”

Those repercussions are becoming clearer though, and the case has been made, most notably by the Stern report, that investing to prevent the heating of the planet is a more cost effective strategy than waiting to deal with the consequences. It is a conclusion on climate change also drawn by US Secretary of State John Kerry: “Early action by human beings can save the world from its worst impacts”.

Humans are now imperfectly adapted to the climate in which they live. The evidence is there in the form of lives lost and property destroyed in ice storms, floods, bush fires and droughts. Events, such as intense rainstorms and droughts, that previously occurred only once in a 1000 years are now happening more frequently. These in turn can translate into mass movements of populations, as it is just not possible – or financially viable – to adapt successfully to every condition. It has recently been acknowledged, including US National Security Advisor Susan Rice, that the drought was a significant driving force in destabilising Syria.

Rapley posed the question: when does the warming of the planet become a dangerous? Politicians rather than scientists have to decide, but nations of the world have set the bar at a temperature increase of 2 degrees – above which the consequences are deemed too severe. We have seen a 0.85 degree increase so far. We will need serious action if we are not to go above the 2 degree ‘guard rail’.

Crucial to success is for politicians to pick up the baton that climate scientists are offering, and to make significant commitments to change. China is taking real leadership in solar generation and the ability to transport electricity by Direct Current grid, and has a commitment to 20% renewables by 2030. Rapley calls for a new generation of engineers to develop convenient and reliable energy that is cleaner and cheaper than fossil fuels. He is optimistic. “Human ingenuity is generally unbounded. We need to liberate, mobilise and support engineers. Who would pay for fossil fuels if they were more expensive as well as dirtier?”

Rapley acknowledges a failure to take the issue to the public in a way that truly engages, and the need to learn from the work of behavioural scientists in understanding how to influence people. “Engaging with the rational mind is all very well, but only for a small part of the population. We are not connecting – we are not getting messages across. Storytelling and legend, which have been around since humanity began, is the way to engage people in new ideas.”

One of Rapley’s efforts has been to collaborate on the development of a play, 2071, that engages people on the idea of legacy. He ended with a quote from that script:

The whole point about climate change is that, despite having been revealed by science, it is not really an issue about science, it is an issue about what sort of world we want to live in.

Professor Rapley’s slides can be viewed here

Many thanks to Professor Rapley for a fascinating start to our 400th anniversary community lecture series. For information about forthcoming lectures and how to book tickets visit

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