Opportunity Understanding the indirect climate impacts of halogens in the troposphere
Lead Research Organisation:
Lancaster University
Department Name: Lancaster Environment Centre
Abstract
Halogen (i.e. chlorine, bromine & iodine) gases are ubiquitous in Earth's atmosphere and since the 1970s
are recognised as the principal driver of stratospheric ozone layer depletion. While the impact of halogens
in the stratosphere is well understood, it is now increasingly recognised that halogens play a far wider role
and may have profound, but overlooked, impacts on the chemical composition of the troposphere - the
lowest region of Earth's atmosphere[1,2]. At the forefront, halogens alter the troposphere's oxidising power
(or "self-cleansing" capacity) and therefore its ability rid itself of pollutants[3-5]. From a climate perspective,
this has important implications as halogens may (i) alter the time greenhouse gases (e.g. methane) remain
in the atmosphere, thereby influencing their warming potential, and (ii) modify the production of aerosol
(microscopic particles suspended in the atmosphere) which effect clouds and cool the climate. Tropospheric
halogens thus possess leverage to influence climate indirectly, though these effects are poorly constrained
as most climate models have yet to consider them.
Working with scientists at the Met Office and University of Leeds, the student will develop and apply a state-of-the-art Earth System Model to quantify the impacts of halogens on the composition of Earth's
troposphere. As understanding of tropospheric halogens is poor (e.g. little is known of how natural halogen
sources have changed over time) there is strong potential for high impact research in this rapidly evolving
field. The project will tackle the following key research questions:
What is the tropospheric abundance/distribution of reactive halogens and how has this changed
during the Anthropocene? What are their key natural/anthropogenic sources?
How do halogens affect the troposphere's regional/global oxidising power and what are the
implications for climate-relevant gases (e.g. methane, volatile organic compounds, tropospheric
ozone) and aerosol?
Do tropospheric halogens affect estimates of pre-industrial to present-day and future climate
radiative forcing?
are recognised as the principal driver of stratospheric ozone layer depletion. While the impact of halogens
in the stratosphere is well understood, it is now increasingly recognised that halogens play a far wider role
and may have profound, but overlooked, impacts on the chemical composition of the troposphere - the
lowest region of Earth's atmosphere[1,2]. At the forefront, halogens alter the troposphere's oxidising power
(or "self-cleansing" capacity) and therefore its ability rid itself of pollutants[3-5]. From a climate perspective,
this has important implications as halogens may (i) alter the time greenhouse gases (e.g. methane) remain
in the atmosphere, thereby influencing their warming potential, and (ii) modify the production of aerosol
(microscopic particles suspended in the atmosphere) which effect clouds and cool the climate. Tropospheric
halogens thus possess leverage to influence climate indirectly, though these effects are poorly constrained
as most climate models have yet to consider them.
Working with scientists at the Met Office and University of Leeds, the student will develop and apply a state-of-the-art Earth System Model to quantify the impacts of halogens on the composition of Earth's
troposphere. As understanding of tropospheric halogens is poor (e.g. little is known of how natural halogen
sources have changed over time) there is strong potential for high impact research in this rapidly evolving
field. The project will tackle the following key research questions:
What is the tropospheric abundance/distribution of reactive halogens and how has this changed
during the Anthropocene? What are their key natural/anthropogenic sources?
How do halogens affect the troposphere's regional/global oxidising power and what are the
implications for climate-relevant gases (e.g. methane, volatile organic compounds, tropospheric
ozone) and aerosol?
Do tropospheric halogens affect estimates of pre-industrial to present-day and future climate
radiative forcing?
Studentship Projects
| Project Reference | Relationship | Related To | Start | End | Student Name |
|---|---|---|---|---|---|
| NE/S007423/1 | 01/10/2019 | 30/09/2027 | |||
| 2888079 | Studentship | NE/S007423/1 | 01/10/2023 | 31/03/2027 | Kathryn Vest |