Atmospheric composition is evolving rapidly with profound consequences for the climate system and human society. We seek to understand the interactions between greenhouse gas and aerosol emissions, atmospheric chemistry and climate change.
Could airborne microplastics play a role in climate change?
Approximately 5 billion tons of plastic waste have accumulated in landfills or the natural environment to date. This will increase to 12 billion tons by 2050 if current trends continue. The breakdown of larger plastics produces microplastics, which are ubiquitous contaminants in waterways, oceans and on land. Recently, microplastics have been discovered in the atmosphere in several megacities and a remote alpine environment. Particulate matter in the atmosphere such as dust and soot modifies atmospheric temperature by interacting with sunlight and clouds. Exactly how it behaves depends on particle size, shape and composition. Because the discovery of
atmospheric microplastics is so recent, we have no idea how they behave – does surrounding air get warmer or colder when sunlight interacts with them? Currently it is completely unknown whether microplastics significantly influence Earth’s climate or not. However given that they are now being discovered in the atmosphere around the world and that their abundance is expected to increase in future, it is important to understand the role of microplastics in a changing climate. We will close this knowledge gap by performing integrated observational, laboratory and modelling studies. Our results will determine whether airborne microplastics will moderate or intensify global warming.
This project is supported by the Royal Society of New Zealand Marsden Fund and will run from 2020 – 2022. It is led by Laura in collaboration with researchers at the University of Canterbury, Victoria University of Wellington and ETH Zurich.
Simulating clouds and aerosols in the New Zealand Earth System Model
The region of the world between Aotearoa New Zealand and Antarctica – the Southern Ocean – plays an important role in influencing New Zealand’s weather and climate. Because it is so remote from most of the world’s population, the Southern Ocean’s atmosphere is considered one of the last pristine locations on the planet. Here the air is relatively clean and the dominant sources of atmospheric particulate matter (“aerosols”) are sea spray and phytoplankton activity. The Southern Ocean is also one of the cloudiest regions on the planet; this presents unique challenges to climate modellers. The 5th Assessment Report (which was published in 2013) of the Intergovernmental Panel on Climate Change confirmed that clouds and aerosols are still a leading source of errors in global climate models. These errors are particularly prevalent over the Southern Ocean where they cascade to errors in simulated sea surface temperature, the position of the storm track, rainfall and extreme weather events in New Zealand. This project aims to improve the representation of clouds and aerosols over the Southern Ocean in New Zealand’s own climate model, the New Zealand Earth System Model (NZESM). The planned research builds on the phase-1 ‘Clouds & Aerosols’ and ‘Sulfate aerosols over the Southern Ocean’ Deep South projects which conducted a variety of relevant observations in the Southern Ocean, helped establish the NZESM and built capacity in microphysics and aerosol research amongst the Deep South community. The phase-1 projects identified several deficiencies in how Southern Ocean clouds and aerosols are represented. We will improve these during the phase-2 research planned here with the overarching goal of improving climate change projections for Aotearoa New Zealand.
This project is supported by the Deep South National Science Challenge and will run from 2020 – 2022. It is led by Laura in collaboration with researchers at the National Institute of Water & Atmospheric Research (NIWA).
Extreme events and the emergence of climate change
Laura is part of an MBIE Endeavour programme led by Victoria University of Wellington which aims to to understand future extreme weather events and their consequences for New Zealand. Laura’s role in the programme is to quantify the role of ozone destruction and recovery in climate change emergence patterns.
Mapping air pollution emissions
We are collaborating with Bodeker Scientific, NIWA, Environment Canterbury and Sigma Space on the Mapping Air Pollution Emissions project, funded by MBIE Smart Ideas. We are measuring and modelling air pollution in Christchurch, New Zealand, and developing novel modelling techniques to trace air pollution to its source. MAPM aims to one day provide city authorities with tools to regulate and enforce air quality standards.
The Chemistry-Climate Model Initiative (CCMI)
Laura Revell is a Principal Investigator for CCMI with the SOCOL (Solar-Climate Ozone Links chemistry-climate model. CCMI is a sub-project of SPARC (Stratosphere-Troposphere Processes and their Role in Climate) and IGAC (International Global Atmospheric Chemistry). CCMI is a multi-model activity through which we seek to understand individual model strengths and weaknesses, and produce projections of the future atmosphere. Papers arising from CCMI are available in the multi-journal ACP/AMT/ESSD/GMD special issue.
Sulfate aerosols over the Southern Ocean
Clouds and aerosols are the leading causes of biases in present-day climate models, particularly over the Southern Ocean. Laura currently leads the ‘Sulfate aerosols over the Southern Ocean‘ project funded by the Deep South National Science Challenge. We are addressing the way marine aerosols form – as a result of phytoplankton activity in the ocean and wave breaking – in the New Zealand Earth System Model (NZESM). The NZESM is based on the UK Met Office Unified Model. By addressing the complexity of cloud droplet chemistry and aerosol formation in the NZESM, we aim to improve the quality of climate change projections for New Zealand.