Anthropogenic emissions of short-lived gases and their environmental impacts

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Global climate directly affects many aspects of our lives such as food security, water resources, and health, thus making climate change one the big challenges of our time. Climate is altered by chemical gases that are released from human activities, but can also originate from the ocean, land and biosphere. We can only advance our understanding of global climate change by investigating the entire Earth system, as the two are connected by complex physical, chemical and biological interactions. The goals of my research are to understand and predict how anthropogenic activities impact atmospheric chemistry and climate by linking the atmosphere with the marine, polar and terrestrial environment. First, I will investigate gases that stem from biological activities in the ocean, so-called marine biogenic trace gases. Marine gases that include bromine and are produced by macroalgae, can contribute to the depletion of the Earth's ozone layer in the upper atmosphere. Large-scale macroalgae farms are currently discussed as an option to remove carbon dioxide from the atmosphere and dampen climate change. However, such farms could lead to a steep increase in the production of brominated gases and threaten ozone recovery. This work will show how macroalgae can impact atmospheric chemistry, air quality and most importantly, global ozone recovery. In particular, I will investigate if macroalgae farms at high latitudes, such as the Canadian shelf zones, are less harmful to the ozone layer than farms in the tropics. Second, my research will focus on future shipping activities and their impact on the Arctic environment. Current climate change leads to dramatic melting of sea-ice, opening the Arctic for economically feasible shipping of cargo and tourisms. Increasing traffic will bring much larger emissions of exhaust gases and particles to the Artic, enhancing air pollution and impacting climate. In addition, these emissions will impact the Arctic Ocean by adding nutrients to the marine environment, thus influencing oceanic production and ecosystems. This work will investigate the impact of future Arctic shipping emissions on air quality and oceanic nutrient supply. In particular, this study will focus on shipping routes through and along the Canadian Arctic Archipelago and their environmental impact. Third, I will investigate anthropogenic pollutants that are emitted from industry, agriculture and wildfires into the atmosphere. I will focus on gases that remain in the atmosphere for less than 1-2 months, so-called short-lived climate forcers. These gases can either warm or cool the environment depending on the species itself, but also on the timing, amount and location of their emission. This work will quantify emissions of short-lived climate forcers, in particular from countries at northern mid- to high latitudes. As these gases play a large role for the Arctic environment, the emission estimates will provide important information on their climate impact.