NASA | Ask a Climate Scientist

Have a question that's always confounded you about Earth's climate? Wonder why it matters that the climate is changing now if it has changed before? Or how scientists know changes seen in recent decades are the result of human activities, not natural causes?

Go ahead. Ask a climate scientist.

NASA scientists will be recording video responses to some of the questions we receive. The responses will be posted to the NASAExplorer YouTube channel.

To submit a question, record a short, 10-15 second video with your question and upload it to YouTube -- and be sure to tag the video "#askclimate" so that we can find it. You can also simply post a question on Twitter with the same hashtag, "#askclimate."

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[slvbackyard]

When I read some of the comments that are lacking good accurate scientific information, I am amazed and concerned. So I think that this"Ask a Climate Scientist" feature is a very good idea. I look forward to future posts.

Fred Mc Ppherson

[johndaddyo]

Easy - read about the "Maunder minimum", EJ. That's a period where the Sun was extremely "quiet". (Very few sunspots, which we now know equates to very low solar energy output)

[johndaddyo]

No, NASA GSFC & NASA MSFC vs NASA GISS. The former representing over 10, 000 scientists and engineers on multiple campuses and in more than 80 buildings on two campuses alone (Greenbelt, MD and Huntsville, AL) working to study Earth using satellites and working to study the solar system using interplanetary space vehicles to measure and observe. The latter representing 160 college students and computer programmers on one floor of one building on the campus of Columbia University - models only.

[eyebo]

Good questions, but I think it needs to be in the form of a short video.

[garith]

1) Most of the atmosphere has nothing to do with GHGs
2) Water vapor is a feedback not a forcing because without warming first it condenses and rains out rather readily.
3) If you think that there's no such thing as a GH effect you need to ask why the dark side of the earth isn't an ice cube every night
4) Part of the reason why we know it's ghgs is because of how and where it's warming the quickest.

[garith]

3) The primary reasons why AGW is the accepted mechanism for the recent warming are because of the physical properties of GHGs, the predictions that have been later observed via the mechanism of GHGs and there's observations that are only consistent with CO2 based warming. If you want to assert it's some other mechanism you need to declare something that's testable in the same manner that just happens to match the fingerprint of GHG based warming.

[johndaddyo]

Actually, the Aqua satellite is tasked to improve the accumulation of cloud data - and you're right, research scientists have struggled to correlate satellite data with the different types of cloud cover. An high school student turned in an excellent early paper on climate change and cloud cover:

"Regional Cloud Cover Change Associated with Global Climate Change: Case Studies for Three Regions of the United States". Meredith S. Croke, 18 December 1998.

[garith]

1) Water vapor isn't uniform in the atmosphere, it actually varies greatly depending on local temperatures, one of the reasons why CO2 is seen as a culprit is because it's got a specific fingerprint and predictions that have been observed. Also water vapor can't increase in terms of climate without temperatures rising and staying consistently higher first or it condenses out quickly.

[garith]

Also they've got specific instructions on how to ask your question, it doesn't involve commenting which would be virtually impossible to comb through reasonably, even if they managed to get a team of interns on it.

[garith]

Actually the local variations were to point out that (if you read the rest of my statement) CO2 has a specific fingerprint as to where and how it should warm the quickest which have been observed. Water vapor can't be a forcing because it doesn't change without a temperature change first.

[johndaddyo]

I can't speak for the majority of NASA's staff. However, I work with quite a few NASA folks in my job, and the ones I know (with a single notable exception) are skeptical of the idea that atmospheric CO2 can drive climate. For non-scientists it's helpful to use analogy: CO2 driving climate change is like the wind driving a Mack truck. Perhaps CO2 might play a role comparing 280 ppmv (0.0028%) to 7000 ppmv (0.7%), like 5 mph vs 125 mph winds, but 280 to 740 ppmv (5 to 15 mph) is insignificant.

[rlindsay]

All planets in our solar system are undergoing big changes...Earth, not so much comparatively to the others. My question is: Can space weather have anything to do with our climate changes here and on the others planets in our solar system? Love your channel & thanks for sharing!

[garith]

1) Many are undergoing changes for various reasons specific to the planets, their respective seasons, some are warming, some are cooling.

2) We know it's not solar activity that's responsible for the warming over the last 3-4 decades as that's been relatively flat for the last 50 years and in fact the sun is being relatively inactive in relation to the last 50 years.

[garith]

3) Usual warming/cooling cycles of the earth are usually from orbital forcing, but these won't be factors again for thousands of years.

4) well there's 2 ideas about the mini ice age, one is thousands of years from now due to orbital forcing(which isn't likely to be a factor with so much ghgs) another is the temporary dimming sun, which is only expected to cool the earth by about .3C if it's another Maunder Minimum type event.

[garith]

because one's been relatively flat in activity if not having a slightly negative effect on temperatures and the other takes over the course of thousands of years.

Also read the description or listen to the video.

[garith]

If you want to assert it's some unknown natural phenomenon you should have some idea of what it is so people can test the idea, the main reasons why AGW is accepted as the best explanation are because of the basic physics of ghgs, observations of the earth, it's reactive forces and where it's warming the quickest are consistent with AGW based warming

[garith]

That's a great assertion, but I'm fairly certain that there's no current study measuring average cloud cover over the surface of the earth, even if there was this assertion ignores the fact that clouds have different effects on warming/cooling depending on when, where and how high in the atmosphere they form.

[garith]

1) Incorrect, the result of how much CO2 in the atmosphere is the total, not "where it came from" We're merely changing the relative rate of how much is being added without sequestering any in the exchange.
2) Incorrect, merely that it's the primary one that is relevant to long term climate since water vapor condenses if there is not warming first.
3) Incorrect, according the IPPC chart regarding residency time it's 5 to 200 years.

[garith]

(cont)

"CO2 does not add to absorption: if anything, it replaces H2O."
Actually this is mistaken, there are some bands of radiation that water vapor does not absorb that CO2 does absorb, we're also by no means at some maximum saturation point where more GHGs cannot result in delayed heat dissipation

[garith]

well, that's reaching towards the end of the error bars, last I saw most studies have a range varying from 75cm to 2 meters. I try not to reach the end of error bars since denialists try to do this with peer reviewed studies suggesting a 1.3C rise in temperatures with a doubling of preindustrial CO2, just as much as I'd reject the other end of the spectrum of a possible 10C.