I am a climate scientist working at Maynooth University in Ireland as the director of the ICARUS Climate Research Centre. I completed my PhD in climate change detection and attribution from the Climatic Research Unit at the University of East Anglia in 2001. Subsequently I worked for the UK Met Office, NOAA's National Centers for Environmental Information (via the CICS-NC cooperative institute), and at the Nansen Centre in Bergen, Norway. My principal historical expertise is in observed climate changes although I have published on multiple aspects of climate change. I was a coordinating lead author on the IPCC AR6 WGI report and a section facilitator on its synthesis report. I am currently the chair of the Global Climate Observing System Atmospheric Observations Panel for Climate and in that capacity sit on several additional GCOS and WMO groups and task teams.Nationally I have been heavily involved in climate policy. I was an external advisor to the citizens assembly deliberations on climate change. I was then an independent advisor to the Joint Oireachtas Committee on Climate Action deliberations.Since 2021 I have been a member of the Climate Change Advisory Council and Chair of its adaptation committee. I also sit on the Central Bank's climate forum.I am the lead on a Copernicus Climate Change Service contract concerned with data rescue, data management and data provision of historical surface meteorological observations. I previously led the H2020 GAIA-CLIM project.