The clarity of the atmosphere above the location where astronomical observations are made has a delicate effect on the accuracy of observations made from the ground. Sites for telescopes are therefore selected with great care. They are frequently located high above sea level to reduce the amount of atmosphere between them and their targets. Clouds and even water vapor prevent a clear view of the night sky, so many telescopes are constructed in deserts.
In a study published in the journal Astronomy & Astrophysics and presented at the Europlanet Science Congress 2022 in Granada, a team of researchers led by the University of Bern and the National Centre of Competence in Research (NCCR) PlanetS demonstrates how one of the greatest challenges of our time — anthropogenic climate change — now affects our view of the cosmos.
A flaw in the selection procedure
“Even though telescopes typically have a lifespan of several decades, site selection processes only account for short-term atmospheric conditions. Typically within the past five years — a period too brief to capture long-term trends, let alone future changes resulting from global warming “The study’s lead author and a researcher at the NCCR PlanetS at the University of Bern, Caroline Haslebacher, explains. Therefore, the team of scientists from the University of Bern and the NCCR PlanetS, ETH Zurich, the European Southern Observatory (ESO), and the University of Reading in the United Kingdom took it upon themselves to demonstrate the long-term perspective.
Worsening conditions on a global scale
Based on their analysis of future climate trends derived from high-resolution global climate models, major astronomical observations from Hawaii to the Canary Islands, Chile, Mexico, South Africa, and Australia will likely experience a rise in temperature and atmospheric water content by 2050. This could result in a loss of observing time and a reduction in the quality of the observations.
“Currently, astronomical observatories are designed to function under the existing site conditions and have limited adaptability. Consequences of the climate for telescopes include an increased risk of condensation due to a higher dew point or malfunctioning cooling systems, which can result in more air turbulence in the telescope dome “Haslebacher says.
Marie-Estelle Demory, co-author of the study, explains that the failure to consider the effects of climate change on observatories in the past was not an oversight, but rather a result of technological limitations “This is the first time such an investigation has been feasible. Due to the higher resolution of the global climate models developed as part of the Horizon 2020 PRIMAVERA project, we were able to examine the conditions at various locations on the globe with greater accuracy than was possible with conventional models. These models are invaluable resources for the Wyss Academy’s work “According to the senior scientist and member of the Wyss Academy of Nature at the University of Bern.
Haslebacher states, “We can now say with absolute certainty that anthropogenic climate change must be accounted for in the site selection for next-generation telescopes and the construction and maintenance of astronomical facilities.”
The clarity of the atmosphere above the location from which astronomical observations are made has a delicate effect on the precision of ground-based observations. Therefore, the locations of telescopes are selected with great care. They are frequently located at a great height above sea level so that less atmosphere separates them from their targets. As clouds and even water vapor obscures the view of the night sky, many telescopes are also constructed in deserts.
