In a paper recently published in Astronomy & Astrophysics, astronomers at the University of Bern stress that anthropogenic climate change – climate change resulting from the influence of human beings on nature – will negatively impact atmospheric conditions at major ground-based observing sites across the globe.
Astronomical observations from ground-based telescopes are extremely sensitive to local atmospheric conditions. The quality of ground-based astronomical observations depends on the clarity of the atmosphere above the observing site from which they are made. Therefore, observations from Earth are often made high above sea level so that there is much less atmosphere between the telescope and the observing target. Additionally, major telescopes are usually located in deserts because these are very dry locations and water vapor and clouds can also negatively impact the quality of astronomical observations.
A team of researchers at the University of Bern and the National Centre of Competence in Research (NCCR) PlanetS claims that anthropogenic climate change is already affecting ground-based astronomical observations. In general, major ground-based observing facilities have lifetimes of several decades. When astronomers are choosing a location for a new telescope, they need to take into account the atmospheric conditions, but the team points out that these types of studies only consider the atmospheric conditions over a short time frame. This time frame is usually only approximately five years, which is much too short to capture any long-term atmospheric trends. In addition, these studies tend to neglect any future changes that may occur due to climate change.
The team decided it was up to them to understand the long-term impact of climate change on major astronomical observing sites. They used high-resolution global climate models to show that major astronomical observatories (located in Hawaii, the Canary Islands, Chile, Mexico, South Africa, Australia, etc.) will likely experience an increase in both temperature and atmospheric water content by 2050.
The increase in both temperature and atmospheric water means that the quality of observations will drastically decrease, and there will also be a loss in observing time when conditions are extreme. Already existing observing sites have been designed and built to work under the current atmospheric site conditions, and thus, it would be difficult to adapt these observatories for changing conditions. As a result, there are some consequences. There would likely be a higher risk of condensation on the instruments due to an increased dew point. Cooling systems may also have to work harder, which may cause them to malfunction, leading to more air turbulence in the telescope dome, which would decrease the clarity of observations.
Therefore, it is imperative to take the effects of climate change into account when planning the construction and maintenance of future ground-based astronomical observing facilities.
Source: University of Bern