Forcings Dr Will Davies, Monitoring and the CAMS 74 team CAMS 2nd General Assembly, Warsaw, 16-18 June 2017 CAMS Climate Forcings

Atmosphere Monitoring • We are a climate-focused service based on the CAMS Reanalysis of Atmospheric Composition.

• We provide estimates and uncertainties of exerted by changes in atmospheric composition caused by human activities.

• Our users are involved in the scientific and policy aspects of . The ’s energy budget

Atmosphere Monitoring • The Earth gets its energy from the Sun, reflects a third of it, absorbs the rest, then emits longwave radiation back to space.

• The Earth’s surface currently takes in more energy than it emits, and warms.

Figure 2.11 of IPCC AR5, 2013 Perturbation by human activities

Atmosphere Monitoring • Increases in greenhouse gases decrease the longwave flux emitted to space.

• Changes in stratospheric and tropospheric ozone perturb shortwave and longwave fluxes.

• Pollution particles (aerosols) increase reflection of shortwave flux to space by interacting with radiation and clouds. Figure 1.01 of IPCC AR5, 2013 Radiative forcing

Atmosphere Monitoring • Radiative forcing quantifies energy budget imbalances

• Positive radiative forcing leads to a gain in energy in the Earth system.

• Negative radiative forcing leads to a loss of energy.

• Current estimates for various forcing agents are from a variety of methods. CAMS Climate Forcing brings consistency. Figure 8.15 of IPCC AR5, 2013 Methodology

Atmosphere Monitoring • To estimate radiative forcing, the CAMS reanalysis of atmospheric composition datasets is used in radiative flux calculations.

• We also use additional observations, and estimates of atmospheric composition before they were perturbed by human activities.

• Strong focus on uncertainties. Expertise

Atmosphere Monitoring • CAMS Climate Forcings gathers top experts of radiation, greenhouse gases, aerosols, and uncertainty quantification. Keith Guy Gunnar Olivier • Teams are based at the Shine Brasseur Myhre Boucher universities of Reading, Leipzig, and Leeds, and at the Max Planck Institute for in Hamburg.

• Taken together, CAMS Climate Forcing experts have contributed Piers Johannes Nicolas Ken to every single IPCC Assessment Forster Quaas Bellouin Carslaw Report since the first in 1990! Version 0 products

Atmosphere Monitoring Average over 2003—2012 Version 0 products

Atmosphere Monitoring • Carbon dioxide and methane radiative forcing increased steadily over 2003—2012

• CO2 +14% • CH4 +2%

• Aerosol radiative forcing was expected to weaken because of decreased emissions to improve air quality, but we find that forcing has in fact remained stable. Product catalogue

Atmosphere Monitoring Forcing agent SW LW TOA Surf All-sky Cloud- free sky Carbon dioxide Methane Coming soon Tropospheric ozone Coming Coming Coming Coming Coming Coming soon soon soon soon soon soon Stratospheric ozone Coming Coming Coming Coming Coming Coming soon soon soon soon soon soon Aerosol-radiation Coming soon Aerosol-cloud N/A

Stratospheric adjustment done in a simplified way, state-of-the- art method coming soon. Version 0 products

Atmosphere Monitoring

http://apps.ecmwf.int/datasets/data/cams-climate-forcings/ CAMS Climate Forcings

Atmosphere Monitoring • We are a climate-focused • CAMS Climate Forcing is: service based on the CAMS – University of Reading Reanalysis of Atmospheric • Nicolas Bellouin, Will Davies, Composition. Keith Shine – University of Leipzig • Johannes Quaas, Johannes • We provide estimates and Muelmenstaedt uncertainties of radiative – University of Leeds • , Ken Carslaw, forcing exerted by changes in Lindsay Lee, Leighton Regayre, atmospheric composition Chris Smith caused by human activities. – MPI-Meteorologie Hamburg • Guy Brasseur, Idir Bouarar, Natalia Sudarchikova • Our users are involved in the – LMD, UPMC, Paris scientific and policy aspects of • Olivier Boucher climate change. – CICERO Oslo • Gunnar Myhre