30 September 2013

Two Lancaster Environment Centre scientists’ work on modeling atmospheric ozone is included in the new report of the UN’s Intergovernmental Panel on Climate Change

Dr Paul Young and Dr Oliver Wild are both experts in modeling the chemistry and composition of the atmosphere. They were invited to contribute to the IPCC’s latest assessment of how the world’s climate is changing and the extent and impact of human activity on climate. The IPCC is the international body charged by the world’s Governments to examine and summarise the evidence of how the world’s climate has changed, and how it is likely to change in the future. 

Paul and Oliver’s contribution looked at the role of ozone. While ozone is beneficial in the stratosphere (higher atmosphere, above 15km), it is a dangerous pollutant in the troposphere (lower atmosphere, below 15km). As well as damaging human and plant health, ozone is a greenhouse gas which contributes to global warming.

“The core experiments commissioned for the report didn’t look at air quality and pollution and how these may have changed over time, and that is where my and Oliver’s work came in,” Paul explained.

Paul led the analysis of a series of models looking at ozone levels from the early years of industrialisation to today and, with Oliver and others, came up with projections of future ozone levels until 2100.

“Overall, the models suggest that  tropospheric ozone has increased by about 30% since 1850, which implies serious effects on human and plant health. Ozone is one of the most important ingredients of air pollution, including smogs,” said Paul.

Oliver’s role focussed mostly on projections of future surface ozone.

“We wanted to investigate how mankind's economic development and industrial activity may affect future air quality. This is important for putting into context the direct effects that climate has on air quality through its effects on our weather,” Oliver said.

“I've also contributed to assessment of the impacts of non-CO2 greenhouse

gases on climate, and in particular to the role of methane, which is both

a greenhouse gas itself and a major precursor of ozone.  Determining how much of the changes in ozone are due to methane and other ozone precursors such as nitrogen oxides (NOx) is important for assessing the contributions that humans make to these changes.”

The report produces a series of projections about ozone levels in the future.

“Scientists  estimating  future pollutant emissions expect that the world is likely to act to reduce ozone as it is has a very measurable negative effect,” Paul said. “So all the projections, apart from the most pessimistic, suggest that the level of ozone in the lower atmosphere will fall by 2100.

Further information:

IPCC report and Summary for Policymakers

Pre-industrial to end 21st century projections of tropospheric ozone from the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP)

Young et al. (2013), Atmos. Chem. Phys. 13, 2063-2090, doi: 10.5194/acp-13-2063-2013. 

Modelling future changes in surface ozone: a parameterized approach

Wild et al. (2012), Atmos. Chem. Phys., 12, 2037-2054, doi: 10.15194/acp-12-2037-2012.