Get NOAA global monthly mean greenhouse gas concentrations

Downloads the NOAA Global Monitoring Laboratory (GML) globally averaged marine surface monthly mean records for carbon dioxide, methane, nitrous oxide, and sulphur hexafluoride. By default each gas is returned in its standard NOAA reporting unit; set units to express every gas on a common scale.

Usage

get_noaa_ghg(gas = c("co2", "ch4", "n2o", "sf6"), units = NULL, quiet = FALSE)

Source

https://gml.noaa.gov/ccgg/trends/

Arguments

gas: Character vector naming one or more gases to download. Any of "co2", "ch4", "n2o", and "sf6" (case insensitive). Defaults to all four.
units: Character string giving the output mole-fraction unit, one of "ppm", "ppb", or "ppt" (case insensitive). When NULL (the default) each gas is returned in its standard NOAA reporting unit (CO2 in ppm, CH4 and N2O in ppb, SF6 in ppt); otherwise every gas is converted to the requested unit.
quiet: Logical. When TRUE progress messages are suppressed. Default FALSE.

Value

A tibble with one row per gas-month and the columns:

gas: Gas name in upper case ("CO2", "CH4", "N2O", "SF6").
date: Month of the observation as a POSIXct, centred on the middle of the month (NOAA's decimal date).
unit: Mole-fraction unit of the value columns ("ppm", "ppb", or "ppt").
average: Globally averaged monthly mean mole fraction.
average_unc: Uncertainty of the monthly mean.
trend: De-seasonalised trend value.
trend_unc: Uncertainty of the trend value.

NOAA reports a negative sentinel (-9.99) when an uncertainty has not yet been calculated; these are returned as NA.

Details

NOAA reports each gas in a different native unit (CO2 in ppm, CH4 and N2O in ppb, and SF6 in ppt). By default these native units are preserved and recorded in the unit column. When units is supplied, every gas is rescaled to that common unit.

The data presented for the most recent year are preliminary and subject to change as reference gases are recalibrated.

These data are made freely available by NOAA GML. When the data are central to a publication, please cite NOAA GML and consider contacting the data providers, who can advise on appropriate use and acknowledgement.

References

Lan, X., Tans, P., & K.W. Thoning: Trends in globally-averaged greenhouse gases determined from NOAA Global Monitoring Laboratory measurements. https://gml.noaa.gov/ccgg/trends/

Dlugokencky, E. J., et al. (1994). The growth rate and distribution of atmospheric methane. Journal of Geophysical Research, 99(D8), 17021–17043. doi:10.1029/94JD01245

Examples

if (FALSE) { # \dontrun{
# All four gases in their standard units, stacked long
ghg <- get_noaa_ghg()

# Convert every gas to ppb
ghg_ppb <- get_noaa_ghg(units = "ppb")

# A single gas
co2 <- get_noaa_ghg("co2")
} # }