  Climate change is affecting and will increasingly affect astronomical
observations. In this paper, we investigated the role some key weather
parameters play in the quality of astronomical observations, and analysed their
long-term trends (longer than 30 years) in order to grasp the impact of climate
change on current and future observations. In this preliminary study, we
specifically analysed four parameters, the temperature, the surface layer
turbulence, the wind speed at the jetstream layer and the humidity. The
analyses is conducted with data from the Very Large Telescope (VLT), operated
by the European Southern Observatory (ESO), located at Cerro Paranal in the
Atacama desert, Chile, which is one of the driest places on Earth. To complete
the data from the various sensors installed at Paranal, we used the fifth
generation and 20th century European Centre Medium-Range Weather Forecasts
(ECMWF) atmospheric reanalysis of the global climate, ERA5 (from 1980 to now)
and ERA20C (from 1900 to 2010), which we interpolated at the Paranal
observatory location. In addition, we also explored climate projections in this
region, using the Coupled Model Intercomparison Project Phase 6 (CMIP6)
multi-model ensemble, under the worst-case climate change Shared Socio-Economic
Pathways (SSP5-8.5) scenario. Further investigation is needed to better
understand the underlying mechanisms of change, as well as to assess the
severity of the impact.
