The imperative to reduce carbon emissions in astronomy

TL;DR

Astronomers need to quantify and reduce their greenhouse gas emissions by prioritizing renewable energy, minimizing air travel, and advocating for sustainable infrastructure to combat climate change effectively.

Contribution

This paper estimates Australian astronomers' emissions and proposes practical strategies for reducing their carbon footprint, emphasizing renewable energy and travel reduction.

Findings

Australian astronomers emit over 25 ktCO2-e/yr from work activities.

Flight emissions correlate with seniority, averaging 37 tCO2-e/yr per astronomer.

Recommends renewable energy use and reduced air travel to lower emissions.

Abstract

For astronomers to make a significant contribution to the reduction of climate change-inducing greenhouse gas emissions, we first must quantify our sources of emissions and review the most effective approaches for reducing them. Here we estimate that Australian astronomers' total greenhouse gas emissions from their regular work activities are $\gtrsim$25 ktCO$_2$-e/yr (equivalent kilotonnes of carbon dioxide per year). This can be broken into $\sim$15 ktCO$_2$-e/yr from supercomputer usage, $\sim$4.2 ktCO$_2$-e/yr from flights (where individuals' flight emissions correlate with seniority), $>$3.3 ktCO$_2$-e/yr from the operation of observatories, and 2.6$\pm$0.4 ktCO$_2$-e/yr from powering office buildings. Split across faculty scientists, postdoctoral researchers, and PhD students, this averages to $\gtrsim$37 tCO$_2$-e/yr per astronomer, over 40% more than what the average Australian non-dependant emits in total, equivalent to $\sim$5$\times$ the global average. To combat these environmentally unsustainable practices, we suggest astronomers should strongly preference use of supercomputers, observatories, and office spaces that are predominantly powered by renewable energy sources. Where facilities that we currently use do not meet this requirement, their funders should be lobbied to invest in renewables, such as solar or wind farms. Air travel should also be reduced wherever possible, replaced primarily by video conferencing, which should also promote inclusivity.