International climate change policy assumes that another 2oc of global warming would be seriously dangerous for the earth. Time lags in the climate system and continuing international dependence on fossil fuels mean that it is now most unlikely that the 2oc change is to be avoided through conventional mitigation of emissions. As a result, Professor Cox argues that it is necessary to adapt to a significant level of climate change. Planning for this scenario needs to take place urgently worldwide.
More dangerously, there is good evidence that the Earth's climate can undergo abrupt changes, called "climate tipping points ", that would be difficult or impossible to adapt to. Examples include the possibility of continual failure of monsoon rains, rapid decline of tropical rainforests and the collapse of the ocean's thermohaline circulation. Surprisingly, climate tipping points may provide some forewarning of their arrival through changes in the yeartoyear variations of the climate. In this talk, Professor Cox explains how scientists are discovering how to read these signals.
There is also a growing international research activity in "Geoengineering ", which is the deliberate intervention in the climate system to counteract manmade global warming. The most promising approach involves mimicking the effects of volcanoes on the climate by injecting bright particles into the upper atmosphere. Such interventions would be very risky as an alternative to dealing with longterm climate change through cuts in emissions. However, they are much fasteracting and so might, in principle, be employed in an emergency to avoid a forthcoming climate tipping point.
In this lecture, Professor Cox discusses the pros and cons of such an approach and asks the question as to whether the international community should design such an emergency geoengineering system to protect the earth against climate tipping points.
Professor Peter Cox is Professor of Climate System Dynamics and leader of Climate Change and Sustainable Futures research at the University of Exeter. His personal research has focussed on interactions between the landsurface and climate, including groundbreaking climate projections. Professor Cox was a leadauthor for the Intergovernmental Panel on Climate Change (IPCC) Assessment Report which won the Nobel Peace Prize in 2007 and is a lead author on the forthcoming IPCC 5th Assessment Report. He is also a member of the Science Advisory Group for the UK Department of Energy and Climate Change and was a member of the Royal Society expert groups on Groundlevel ozone in the 21st century and Geoengineering the climate. Professor Cox researches and lecture worldwide, is the winner of numerous awards and is amongst the most highlycited authors about climate change.
The Royal Geographical Society Hong Kong wishes to express its thanks to KPMG for its generous assistance with this lecture.