Research infrastructures have been identified as an important source of greenhouse gas emissions of astronomical research. Based on a comprehensive inventory of 1,211 ground-based observatories and space missions, we assessed the evolution of the number of astronomical facilities and their carbon footprint from 1945 to 2022. We found that space missions dominate greenhouse gas emissions in astronomy, showing an important peak at the end of the 1960s, followed by a decrease that has turned again into a rise over the last decade. Extrapolating past trends, we predict that greenhouse gas emissions from astronomical facilities will experience no strong decline in the future, and may even rise substantially, unless research practices are changed. We demonstrate that a continuing growth in the number of operating astronomical facilities is not environmentally sustainable. These findings should motivate the astronomical community to reflect about the necessary evolutions that would put astronomical research on a sustainable path.

研究基础设施已被确定为天文研究温室气体排放的重要来源。基于对 1,211 个地面观测站和太空任务的全面清查，我们评估了 1945 年至 2022 年天文设施数量及其碳足迹的演变。我们发现，太空任务在天文学中的温室气体排放中占主导地位，呈现出一个重要的峰值20 世纪 60 年代末，下降，随后在过去十年再次转为上升。推断过去的趋势，我们预测天文设施的温室气体排放在未来不会出现大幅下降，甚至可能大幅上升，除非研究实践发生改变。我们证明，运行中的天文设施数量的持续增长不利于环境可持续发展。这些发现应该激励天文学界反思必要的演变，使天文学研究走上可持续的道路。