Impact of the biosphere on atmospheric aerosol and climate

Lead Research Organisation: University of Leeds
Department Name: School of Earth and Environment

Abstract

Understanding climate change is one of the most important challenges facing science today. Atmospheric particles (aerosols) have an important cooling impact on the Earth, partly counteracting greenhouse gas warming over the industrial period. Quantifying this aerosol cooling is a critical step to making more accurate predictions of climate change. Considerable effort has been put into assessing the climate impact of anthropogenic (man-made) particle emissions. This proposal focuses on natural biogenic aerosol, which has been much less studied and is poorly understood. However, we need to understand the natural situation before we can fully understand how mankind is changing the atmosphere and the climate. Vegetation emits organic species to the atmosphere (the cause of the well known forest pine smell) where they can react to form particles. Vegetation also directly emits particles such as pollen and fungal spores. Observations have shown that these natural biogenic aerosol emissions can dominate the total particle load in much of the atmosphere. The particles cool the climate by reflecting sunlight and by making clouds thicker and more reflective. We also know that rain droplets form on these tiny biological particles and so they can play a role in controlling worldwide rainfall patterns. Despite such obvious importance, current climate models have a very limited representation of biological particle sources and so their importance for regulating climate is not well known. As the climate changes ecosystems will respond: plant activity such as photosynthesis is modified and vegetation distributions are changed. These changes modify biogenic aerosol emissions changing the amount of particles in the atmosphere with consequent impacts on aerosol cooling. Such climate feedbacks may dampen or amplify anthropogenic global warming. That is, as the world warms particle emissions from the forests may increase helping to cool the climate. In this way forests may act as a global 'air conditioner'. But we don't know how important this effect is because these interactions have not yet been treated by climate models. Tropical deforestation is rapidly changing land-cover but the impacts on climate are not well known because climate models do not treat all the necessary interactions between vegetation and climate. There is also interest in intentionally modifying land-use to mitigate climate change. For example, afforestation absorbs carbon dioxide into vegetation and could be used as a carbon-sink to offset greenhouse gas emissions from fossil fuel use. But the impact to climate of such changes to land-use is poorly known. Recent studies suggest that afforestation at high-latitudes (for example, in Europe) may actually warm the climate because dark forest vegetation absorbs more sunlight than snow-covered farmland. But these previous studies ignored particle emissions from the forest and their impact on climate. My own research has shown that these forest-derived particles result in an important cooling that can play a significant role in the net climate impact of land-use change. In this fellowship I will substantially improve our understanding of natural particles from the biosphere. I will include a comprehensive treatment of vegetation particle emissions in climate models for the first time. I will answer the fundamental question of how terrestrial biosphere emissions regulate global aerosol and climate. Finally, through an integrated assessment of different ecosystem-climate interactions I will improve our understanding of how changes to land-use alter climate.

Publications

10 25 50
 
Description Findings from research have influenced UK government biofuel policy.
First Year Of Impact 2009
Sector Environment
Impact Types Societal

 
Description Environmental Audit Committee
Geographic Reach National 
Policy Influence Type Gave evidence to a government review
Impact Change to UK Biofuel Policy to include mandatory sustainability criteia
URL http://www.publications.parliament.uk/pa/cm200708/cmselect/cmenvaud/76/76.pdf
 
Description United Bank of Carbon 
Organisation United Bank of Carbon
Country United Kingdom 
Sector Private 
PI Contribution Our research contributes to the overall aim of the United Bank of Carbon: "to protect the world's forests and their peoples".
Collaborator Contribution United Bank of Carbon has contributed funds towards a PhD studentship.
Impact Collaboration has facilitated £1.8 million public and private sector investment in forest conservation, managed 15 forest conservation projects worldwide and contributed to the protection of over 250,000 hectares of the world's forests.
Start Year 2009
 
Company Name United Bank of Carbon 
Description Not-for-profit registered charity 
Year Established 2009 
Impact UBoC facilitated £1.8 million public and private sector investment in forest conservation, managed 15 forest conservation projects worldwide and contributed to the protection of over 250,000 hectares of the world's forests.
Website http://www.unitedbankofcarbon.com
 
Description Environment Audit Committee 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? Yes
Geographic Reach National
Primary Audience Policymakers/politicians
Results and Impact Gave expert evidence at the Environment Audit Committee on "Are biofuels sustainable?"

The Environmental Audit Committee produced a report "Are Biofuels Sustainable?" http://www.publications.parliament.uk/pa/cm200708/cmselect/cmenvaud/76/76.pdf
The report influenced Uk government biofuel policy to include mandatory sustainability criteria,
Year(s) Of Engagement Activity 2008
URL http://www.publications.parliament.uk/pa/cm200708/cmselect/cmenvaud/76/76.pdf
 
Description Media 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Media (as a channel to the public)
Results and Impact Research has been covered in national and International media including print and on-line newspapers, radio and TV. I was interviewed twice on BBC Breakfast.

Broader understanding of environmental issues
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013,2014
 
Description United Bank of Carbon Presentations 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Presentations have been made to various businesses across the UK on the role of forests in climate mitigation and adaptation.

Talks facilitated £1.8 million public and private sector investment in forest conservation.
Year(s) Of Engagement Activity 2008,2009,2010,2011,2012,2013,2014
 
Description Various public presentations 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Public/other audiences
Results and Impact Discussion and short write-up in local newsletter

Increased interest from members of the public, enquiries
Year(s) Of Engagement Activity 2009,2010,2011,2012,2013,2014