SIGPLAN and Climate Change


Climate change due to human emissions of greenhouse gases is an urgent threat, one that requires massive efforts at every level of society. SIGPLAN (and ACM and other scientific societies more broadly) contribute disproportionately to this threat by hosting conferences that are responsible for large amounts of carbon emissions, primarily as a result of participants’ air travel.

The SIGPLAN Climate Committee recognizes this dilemma and consequently seeks to study and address SIGPLAN and ACM’s role in climate change.

About the SIGPLAN Climate Committee

In 2017, SIGPLAN formed an ad hoc committee to study the climate impact of conferences and possible steps that SIGPLAN might take in response.

The SIGPLAN Climate Committee is chaired by SIGPLAN Vice-Chair Benjamin Pierce; its other members are SIGPLAN Chair Jens Palsberg, Past EC member Crista Lopes, and Past SIGPLAN Chair Michael Hicks.

Air travel is a significant source of greenhouse gas emissions, which in turn are a significant contributor to climate change. SIGPLAN hosts a number of annual scientific meetings at various locations throughout the world. While such meetings are important for furthering important research, we need to explore possible mitigations. Accordingly, the SIGPLAN Climate Committee has taken several steps in examining and addressing this issue.

What the Climate Committee has done so far

In 2017, the Climate Committee began raising issues of climate change and air travel with the SIGPLAN community, conducting surveys and discussions. The Committee also began its own research and studies into the issue.

In 2018, the Climate Committee issued an interim report (current version June 2018), which summarizes a number of ideas under consideration and some experiments currently underway, following intensive discussions within the committee and with the overall community at town hall meetings. The Climate Committee also issued a white paper on carbon offset purchasing.

In the fall of 2018, the Committee asked the SIG Governing Board to make a request to ACM to investigate legal barriers to ACM conferences’ directly purchasing carbon offsets or offering the purchase of carbon offsets to conference attendees at registration. The result was ACM’s new carbon offset policy. Work continues on implementing and improving the policy.

The Climate Committee also initiated the development of ACM’s Carbon Calculator for conferences. This tool allows a conference planner to upload a spreadsheet of attendees’ origin cities to estimate the emissions due to air travel for an entire conference.

In summer 2019, The Climate Committee authored a SIGPLAN blog post calling for (1) public accounting of carbon emissions by every ACM conference, and (2) pricing of carbon in conference budgets.

What the Climate Committee is doing

The Committee will be publishing an upcoming article on these topics in Communications of the ACM (CACM) journal.

We are working with other SIGs on a data gathering and analytics project around measuring carbon emissions from past conferences and calculating emissions for future conferences. For instance, we may be able to predict relative carbon emissions from different conference locations, or from co-locating several conferences. Some scripts written for these purposes can be found on Github.

We continue to

  • make sure that climate change is on the agenda at the SGB level
  • investigate how ACM conferences might directly purchase carbon offsets
  • make presentations at major SIGPLAN conferences

How you can help

Anyone interested in participating in discussions about SIGPLAN and climate change is invited to join the acm-climate email discussion group.

If you’d like to contribute time and energy, let us know – we’ve got plenty of things to work on!

Carbon Offsets

One recent major effort has been evaluating the idea of carbon offsets as a mechanism for reducing the conference’s net carbon impact. A report on what we have learned is available.

Carbon offsets have the potential to reduce SIGPLAN’s net carbon impact while furthering sustainability and developmental goals. They help fund projects that would not otherwise be economically feasible given start-up costs or the means of the communities they are servicing. Ideally, they address the potential trade-off between reducing carbon emissions and furthering the progress of less-developed parts of the world. They are not a long-term solution to the problem of carbon emissions from scientific conferences, but they are a useful stopgap, slowing the overall growth of atmospheric greenhouse gas concentrations while other fossil fuel reduction strategies are being developed. An excellent discussion of the pros and cons of carbon offsets in general and of specific project types can be found in a recent report from the Stockholm Environmental Institute.

The carbon offset vendor that SIGPLAN currently works with is CoolEffect. For example, check out their project that funds building converters from cow manure to biogas.

For those that like comparison shopping, Atmosfair is another excellent vendor. It is a non-profit originally created as part of a research project by the German Federal Ministry for the Environment. Its carbon offset projects are registered through the UN Clean Development Mechanism (CDM) standard and are either approved by or awaiting approval under the Gold Standard — these are widely recognized vetting groups.

More Resources

SIGPLAN Climate Committee Publications and Talks