2022 Year in Review
The good, the bad and the ugly
Climate science focuses on two fundamental issues: the current status of the changed climate; and, projections of future changes in the climate. The science is not “settled” regarding either of these issues.
The key aspects of interest regarding the current status of the changed climate are: atmospheric GHG concentration; global average near-surface temperature; tropospheric temperature; sea level; extreme weather events; and, ocean pH. Projections of future changes in the climate also focus on these issues and rely on climate models.
The Mauna Loa data on the atmospheric concentration of CO2 are broadly accepted and document a rough doubling of the atmospheric CO2 concentration since the pre-industrial period.
The global average near-surface temperature data and sea surface temperature data remain problematic as the result non-uniform global coverage, particularly in the Southern hemisphere and in the global oceans, urban sprawl, aging and malfunctioning measuring stations and large areas with no measuring stations. This continues to result in “adjusting” measurements and “infilling” estimates where no data are available. The US Climate Reference Network continues to demonstrate the ability to measure near-surface temperature accurately and reliably, but there appears to be little interest in establishing such a network on a global basis.
The tropospheric temperature data provide almost complete global coverage and indicate a slower rate of warming than the near-surface temperature anomaly products. The reasons for this discrepancy remain unexplained.
The sea level data are also problematic. The rate of sea level rise measured by satellite is approximately twice the rate of increase measured by geologically stable tide gauges. This discrepancy also remains unexplained.
There are no increasing trends in the frequency, severity or duration of extreme weather events, including floods, droughts, tropical cyclones or tornadoes, despite frequent political handwringing to the contrary.
Ocean pH has decreased very slightly but remains solidly basic at 8+.
There are numerous climate models used to project future global near-surface temperature change. All the models have projected temperature increases greater than observed, on average nearly twice as great. None of the models have been validated and verified. The models influence and are influenced by climate sensitivity, climate forcings and feedbacks, as well as by the Representative Concentration Pathway (RCP) selected to estimate future atmospheric CO2 increases.
The climate sensitivity to a doubling of atmospheric CO2 is unknown, but is estimated to range from 1.5 – 4.5 degrees C. Recent research suggests that sensitivity is near, or even below, the bottom of that range. The magnitude of climate forcings are also estimated. The magnitude and direction of climate feedbacks are also unknown but estimated. Finally, the rate at which additional CO2 will accumulate in the atmosphere is unknown, though there are several Representative Concentration Pathways in current use. The combination of these uncertainties results in model projections of future temperatures which vary significantly and diverge rapidly into the future.
The most commonly used RCP is RCP8.5, which projects the greatest increase in atmospheric CO2 concentrations. RCP8.5 has frequently been referred to as the “business-as-usual” scenario, though there is growing recognition that it is implausible. It does, however, produce the scariest scenarios of future climate catastrophe.
Models are also being used to attempt to attribute some fraction of some extreme weather event to climate change. However, these models are also unverified and unvalidated. Most recently, there has been a growing effort to provide “instant attribution” to take advantage of the news cycle immediately after the event.