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At a glance - The difference between weather and climate

Posted on 23 April 2024 by John Mason, BaerbelW

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.


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


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