“Above average temperatures expected for the month of February”
Can’t predict a cold snap three weeks out, but confident on climate 20 years out.
“Listen to the experts!”
An example of the sort of ignorant dismissal of climate science that results from partisan political abuse of the subject.
Climate =/= weather. A fact that clearly escapes a lot of people. Climate is the manifold of weather states
and is an energetic constraint on the realization of those states. No climate scientist claims to be forecasting
weather states. They are using the observed and assured through further release of CO2, CH4, etc., compositional
changes in the atmosphere to "forecast" the energy envelope of accessible weather states of the relatively near future.
Weather forecasting beyond one week is well known to be unreliable since we are dealing with a nonlinear dynamical
system. Small perturbations grow into dominant structures on the timescale of days. Essentially a one or two day
forecast is sitting in the quasi-linear regime and thus makes sense. We do not have the infinite observational
network and god-like supercomputers to be able to make forecasts for periods well beyond 4 days.
Seasonal weather forecasting is better framed as a probability distribution than any actual forecast. So
you takes your chances. This has nothing to do with climate since climate is not about the nonlinear dynamics.
In the global average the dynamics averages out and the remaining element is the radiative transfer which is
tied to the chemical composition of the atmosphere. The nonlinear dynamics is to some extent hidden in the
compositional state, but thanks to mixing we do not have substantial heterogeneity. The nonlinearity
also shows up as feedback effects such as water vapour in the atmosphere and the surface albedo. The uncertainty
in climate simulations is the cloud albedo and carbon reservoir release. Industrial activity is another issue since
we saw with the PCFCs in paint cans and other uses that warming can be put on steroids since PCFCs have
IR absorption levels 10,000s of times higher than CO2. So PCFCs in parts per billion are more than enough
to mess us up. Ironically, it was the concern over the ozone layer that saved us from this climate catastrophe.
Climate simulations have real value for "forecasting" the accessible energy of the atmosphere-ocean-land system.
They are also done as ensembles since weather is not the focus and is a derivative effect. People who piss on
climate science typically invoke the non-argument of variability. They do not understand what variability is.
They think that variability applies to the radiative transfer properties of CO2. No it does not. The effects of
CO2 and the other greenhouse gases are deterministic and their effects are known through well over a
hundred years of laboratory work. These pissers confuse the dynamical variability with physical process variability.
The thermal effects of CO2 do not care about transport by the winds. But weather is all about such transport.
You can thank God that water is constrained on this planet. If our climate state was purely linked to the variability
of water loading in the atmosphere, then life would have been wiped out if it ever formed at all on this planet. A
self-amplifying loading of H2O in the atmosphere would result in a Venus regime. H2O is more potent as a greenhouse
gas than CO2. But the trick is that it condenses since it is a molecule with a high electric moment compared to
CO2. H2O is what allowed the Earth to lose its 95% CO2 atmosphere even though under such conditions both
are in the Venus hothouse regime. Venus never got out of its hothouse because it lost H2O to space. It may
never had the amount that Earth had to start with, but the bottom line is that H2O will act to accelerate cooling
by forming a condensing convection cycle.
As H2O raises to the top of the hothouse atmosphere it starts to cool and condense and radiates IR very efficiently
at altitudes where CO2 is optically thin, so the IR is lost to space. Right now on Earth this transition zone is
at around the tropopause level. When the Earth was in the hothouse state, this zone would have been maybe
around 70 to 100 km. CO2 does not behave this way since it is a non-condensing dry gas. Under current conditions
H2O simply cannot induce a runaway warming without dry greenhouse gases like CO2 to help it. Suppose that
deus ex machina H2O was increased by some fraction with the other gases kept the same. This would initially
increase global mean temperatures, but it would also mean more precipitation at high latitudes (snow and ice albedo
would go up) and there would not be any warming effect in the polar caps as with CO2. It would also mean that
the convective heat pumping would increase leading to more IR energy loss to space. Convection acts as a thermal
valve in the system. The high latitude removal of moisture would not just apply to local H2O, it would also be a
sink for low latitude moisture through the transport by baroclinic eddies. The relative role of additional evapouration
of H2O and its losses can be very well quantified with 3D chemical-transport models and the loss processes are
too fast for the initial H2O injection to sustain itself or grow. High latitude surface albedo is an important part of
this control. Under current conditions the system is not unstable to H2O increases. That is why we can have
life on this planet.