We are pleased to announce the launch of EARLICOST, a new COST Action dedicated to advancing atmospheric lidar technologies and strengthening collaboration across Europe and beyond.

EARLICOST aims to deepen our understanding of atmospheric composition and enhance the capabilities of atmospheric lidars to address critical gaps in aerosol characterization, temperature, and water vapour profiling. The vertical distribution of these key atmospheric variables provides essential insights into air quality, public health, weather systems, and climate processes.

Aerosols, in particular, are among the most significant drivers of climate change and remain one of the largest sources of uncertainty in climate models. Their complex interactions with radiation and clouds, combined with their strong spatial and temporal variability, make them a crucial yet challenging component of the Earth system. Improving how we observe and interpret aerosol properties is therefore fundamental for more reliable climate predictions and better-informed environmental policies.

Although important technological breakthroughs in atmospheric lidar systems have been achieved by research institutions and industry, there is still a pressing need to strengthen knowledge-sharing, harmonise methodologies, and enhance collaboration between scientific communities, technology developers, and end users.

EARLICOST responds to this need by fostering a multidisciplinary network that brings together academic researchers, industry experts, policymakers and commercial and scientific end users. The Action builds on the current state-of-the-art in lidar technology and aims to:

• Harmonise measurement methodologies across networks
• Standardise aerosol, water vapour, and temperature retrievals
• Develop innovative techniques to improve the accuracy of atmospheric profiling
• Promote technological innovation and improved data-sharing practices

By advancing lidar technologies and strengthening cooperation across sectors, EARLICOST will contribute to a better understanding of atmospheric processes and deliver tangible societal benefits — from improved air quality monitoring to more accurate climate predictions and evidence-based environmental policies.