Due to popular demand (and thanks to Steve Fish), here is a list of commonly used acronyms on this site:

• ACC= Anthropogenic Climate Change
• AGU= American Geophysical Union
• AGW= Anthropogenic Global Warming or (less often) Atmospheric Gravity Waves
• AMO=Atlantic Multidecadal Oscillation
• AMS= American Meteorological Society
• AO= Arctic oscillation (very similar to NAO)
• AOGCM= Atmosphere-Ocean General Circulation Model
• APS= American Physical Society
• AR4= Fourth Assessment Report (IPCC)
• AR5= Fifth Assessment Report (IPCC) (due 2013)
• Argo float= Ocean temperature measuring device
• AVE= Atmospheric Vortex Engine
• BAU= Business As Usual
• BEST= Berkeley Earth Surface Temperature project
• CCD= Carbonate Compensation Depth = depth at which carbonates dissolve in the ocean
• CCN= Cloud Condensation Nuclei
• CCS= Carbon Capture Storage
• CET= Central England Temperature
• CFR= Climate Field Reconstruction
• CME= Coronal Mass Ejections
• CRF= Cosmic Ray Flux
• CTD= Conductivity/Temperature/Depth. Probe for measuring ocean conditions
• CWC= Cloud (liquid) Water Content
• DTR= Diurnal Temperature Range
• ECS= Equilibrium Climate Sensitivity (Charney sensitivity)
• EMR= Electromagnetic Radiation
• ENSO= El Niño-Southern Oscillation
• EROI= Energy Return on Investment
• ESS= Earth System Sensitivity = Whole system response to radiative forcing
• FOI= Freedom of Information Act
• GCM= Global Circulation/Climate Model (AOGCM)
• GCR= Galactic Cosmic Rays
• GFD= Geophysical Fluid Dynamics
• GFDL= Geophysical Fluid Dynamics Laboratory (NOAA)
• GHE= Greenhouse Effect
• GHG= Greenhouse Gas
• GIS= Greenland Ice Sheet
• GISS= Goddard Institute for Space Studies (part of NASA)
• GISTEMP= GISS Surface Temperature Analysis
• GMST= Global Mean Surface Temperature (anomaly)
• GRL= Geophysical Research Letters (an AGU journal)
• GWP= Global Warming Potential
• HEV= Hybrid Electric Vehicle
• ICE= Internal Combustion Engine
• IERS= International Earth Rotation & Reference Systems Service
• IJOC= International Journal of Climatology
• IOC= Intergovernmental Oceanographic commission
• IPCC= Intergovernmental Panel on Climate Change
• ISO= Intra-Seasonal Oscillation (synonymous with MJO)
• ISW= Ice Shelf Water
• ITCZ= Intertropical Convergence Zone
• JGR= Journal of Geophysical Research (an AGU journal)
• LGM= Last Glacial Maximum (about 20,000 years ago)
• LIA= Little Ice Age
• LTE= Local Thermodynamic Equilibrium
• LW= Longwave (infra-red radiation)
• MCA= Medieval Climate Anomaly
• MDR= Main Development Region (for Atlantic hurricanes)
• MJO= Madden-Julian Oscillation (or Intra-Seasonal Oscillation)
• MOC= Meridional Overturning Circulation (ocean)
• MWP= Medieval Warm Period (MCA is probably more apt)
• NAO= North Atlantic Oscillation
• NH= Northern Hemisphere
• OHC= Oceanic Heat Content
• OLR= (also OLW) Outgoing Longwave Radiation
• PCA= Principal Component Analysis
• PDF= Probability Density Function
• PDO= Pacific Decadal Oscillation
• PETM= Paleocene Eocene Thermal Maximum
• PHEV= Plug-in Hybrid Electric Vehicle
• PNAS=Proceeding of the National Academies of Science (a journal)
• RCS= Regional Curve Standardization (method for processing tree ring data from different trees)
• RH= Relative Humidity
• RMS= Royal Meteorological Society (or Root Mean Square)
• SAM= Southern Hemisphere Annular Mode (positive= wind belt around Antarctic stronger= colder)
• SAR= Second Assessment Report (IPCC)
• SLR= Sea level rise
• SOI= Southern Oscillation Index (see ENSO)
• SPE= Solar Proton Event
• SPM= Summary for Policy Makers (usually with respect to IPCC reports)
• SRM= Solar Radiation Management
• SSM= Standard Solar Model
• SST= Sea Surface Temperature
• STP= Standard Temperature and Pressure (a reference for physical properties)
• SW= Shortwave (solar) radiation
• TAR= Third Assessment Report (of the IPCC)
• TC= Tropical Cyclone (any hurricane)
• TCR= Transient Climate Response
• THC= Thermohaline Circulation (that driven by temp and salinity effects)
• TOA= Top-of-the-atmosphere
• TSI= Total Solar Irradiance
• WAIS= West Antarctic Ice Sheet
• WMO= World Meteorological Organization
• XBT= eXpendable Bathy-Thermograph (deep ocean temperature measuring devices)