At a glance - The difference between weather and climate

On February 14, 2023 we announced our Rebuttal Update Project. This included an ask for feedback about the added "At a glance" section in the updated basic rebuttal versions. This weekly blog post series highlights this new section of one of the updated basic rebuttal versions and serves as a "bump" for our ask. This week features "The difference between weather and climate". More will follow in the upcoming weeks. Please follow the Further Reading link at the bottom to read the full rebuttal and to join the discussion in the comment thread there.

Fact-Myth-Box

At a glance

How do you go about weather forecasting by yourself? Study the computer models. With experience, you will become familiar with the art - for it takes human interpretation of model output to make the calls. That's what weathermen do.

Forecast model output is freely available online and covers many parameters - pressure, temperature, rainfall and a myriad of others. Different models extend to different end-times - the Global Forecasting System (GFS) extends to T+ 384 hours or 16 days, for example. Pressure, or synoptic charts as they are known, portray the positions and subsequent developments of high and low pressure systems over large swathes of the planet.

Models are run several times a day. If you examine synoptic charts for the same run of several different models, you will see they all look very similar to start with. But if you then follow them through successive time-points - T+24, 48, 72 hours and so on, there will come a point where you start to notice slight and then larger differences between them. This divergence is where confidence in forecasting falls right away.

Forecasting - interpreting the GFS and other model output - is about working with uncertainty in the highly dynamic and to an extent chaotic medium that is our atmosphere. But with experience, you can do your own short term forecasting too, at least for the coming 3-5 days.

Longer-term weather forecasting a week or more in advance is about stating probabilities, not saying what will happen. Very different things. Serious amateur forecasters stick to the shorter, next few days bracket, if they want to avoid egg on their faces. There are a few out there who often make wild claims that usually fail to be borne out by reality. Unfortunately, sections of the more populist media happily quote them. It generates click-baity headlines.

Now, what about climate? Climate differs from weather because it includes certain highly deterministic drivers. Deterministic means they evolve independently of weather but can change the physical conditions on Earth from state A to state B. Cyclic variations in Earth's orbit of the Sun, operating over tens of thousands of years, are a good example. They may only drive average planetary temperature changes of a few degrees Celsius, upwards or downwards. But with the help of climate feedbacks, that is enough to have caused past ice-ages - and to have gotten us out of them again.

Changes in the strength of Earth's greenhouse effect are likewise deterministic, but to a far greater extent. They have forced past transitions from the Hothouse to the Icehouse climate state. Hothouse, by the way, is an ice-free Earth. Because we know how the greenhouse effect works, we can say with confidence that intensifying its strength will cause global temperatures to rise over centuries. What we cannot say is what weather will occur on a certain day at a certain place, decades from now. But there's a handy saying to cover that: "climate trains the boxer, but the weather throws the punches". (Deke Arndt, Climate Monitoring Branch Chief, NCDC, 2010)

Please use this form to provide feedback about this new "At a glance" section. Read a more technical version below or dig deeper via the tabs above!


Click for Further details

In case you'd like to explore more of our recently updated rebuttals, here are the links to all of them:

Myths with link to rebuttal Short URLs
Ice age predicted in the 1970s sks.to/1970s
It hasn't warmed since 1998 sks.to/1998
Antarctica is gaining ice sks.to/antarctica
CRU emails suggest conspiracy sks.to/climategate
What evidence is there for the hockey stick sks.to/hockey
CO2 lags temperature sks.to/lag
Climate's changed before sks.to/past
It's the sun sks.to/sun
Temperature records are unreliable sks.to/temp
The greenhouse effect and the 2nd law of thermodynamics sks.to/thermo
We're heading into an ice age sks.to/iceage
Positives and negatives of global warming sks.to/impacts
The 97% consensus on global warming sks.to/consensus
Global cooling - Is global warming still happening? sks.to/cooling
How reliable are climate models? sks.to/model
Can animals and plants adapt to global warming? sks.to/species
What's the link between cosmic rays and climate change? sks.to/cosmic
Is Al Gore's An Inconvenient Truth accurate? sks.to/gore
Are glaciers growing or retreating? sks.to/glacier
Ocean acidification: global warming's evil twin sks.to/acid
The human fingerprint in global warming sks.to/agw
Empirical evidence that humans are causing global warming sks.to/evidence
How do we know more CO2 is causing warming? sks.to/greenhouse
Explaining how the water vapor greenhouse effect works sks.to/vapor
The tricks employed by the flawed OISM Petition Project to cast doubt on the scientific consensus on climate change sks.to/OISM
Is extreme weather caused by global warming? sks.to/extreme
How substances in trace amounts can cause large effects sks.to/trace
How much is sea level rising? sks.to/sealevel
Is CO2 a pollutant? sks.to/pollutant
Does cold weather disprove global warming? sks.to/cold
Do volcanoes emit more CO2 than humans? sks.to/volcano
How do human CO2 emissions compare to natural CO2 emissions? sks.to/co2
Climate scientists could make more money in other careers sks.to/money
How reliable are CO2 measurements? sks.to/co2data
Do high levels of CO2 in the past contradict the warming effect of CO2? sks.to/pastco2
What is the net feedback of clouds? sks.to/cloud
Global warming vs climate change sks.to/name
Is Mars warming? sks.to/mars
How the IPCC is more likely to underestimate the climate response sks.to/underestimat
How sensitive is our climate? sks.to/sensitivity
Evidence for global warming sks.to/warming
Has the greenhouse effect been falsified? sks.to/falsify
Does breathing contribute to CO2 buildup in the atmosphere? sks.to/breath
What is causing the increase in atmospheric CO2? sks.to/CO2increase
What is methane's contribution to global warming? sks.to/methane
Plants cannot live on CO2 alone sks.to/plant
Is the CO2 effect saturated? sks.to/saturate
Greenhouse warming 100 times greater than waste heat sks.to/waste
How will global warming affect polar bears? sks.to/bear
The runaway greenhouse effect on Venus sks.to/venus
What climate change is happening to other planets in the solar system? sks.to/planets
Has Arctic sea ice returned to normal? sks.to/arctic
Was Greenland really green in the past? sks.to/green
Is Greenland gaining or losing ice? sks.to/greenland
Human activity is driving retreat of Arctic sea ice sks.to/arcticcycle
The albedo effect and global warming sks.to/albedo
Does CO2 always correlate with temperature? sks.to/correlate
Human fingerprints on climate change rule out natural cycles sks.to/cycle
Global warming and the El Niño Southern Oscillation sks.to/elnino
The Pacific Decadal Oscillation (PDO) is not causing global warming sks.to/pdo
Is the science settled? sks.to/settled
The difference between weather and climate sks.to/weather

 

If you think that projects like these rebuttal updates are a good idea, please visit our support page to contribute!

Posted by John Mason on Tuesday, 23 April, 2024


Creative Commons License The Skeptical Science website by Skeptical Science is licensed under a Creative Commons Attribution 3.0 Unported License.