Increase In Atmospheric Moisture Tied To Human Activities

http://www.terradaily.com/reports/Increase_In_Atmospheric_Moisture_Tied_To_Human_Activities_999.html

The water vapor feedback mechanism works in the following way: as the atmosphere warms due to human-caused increases in carbon dioxide, methane, nitrous oxide, and chlorofluorocarbons, water vapor increases, trapping more heat in the atmosphere, which in turn causes a further increase in water vapor.

by Staff Writers

Livermore CA (SPX) Sep 19, 2007

Observations and climate model results confirm that human-induced warming of the planet is having a pronounced effect on the atmosphere's total moisture content. Those are the findings of a new study appearing in the Sept. 17 online edition of the Proceedings of the National Academy of Sciences. "When you heat the planet, you increase the ability of the atmosphere to hold moisture," said Benjamin Santer, lead author from Lawrence Livermore National Laboratory's Program for Climate Modeling and Intercomparison.

"The atmosphere's water vapor content has increased by about 0.41 kilograms per cubic meter (kg/m²) per decade since 1988, and natural variability in climate just can't explain this moisture change. The most plausible explanation is that it's due to the human-caused increase in greenhouse gases."

More water vapor - which is itself a greenhouse gas - amplifies the warming effect of increased atmospheric levels of carbon dioxide. This is what scientists call a "positive feedback."

Using 22 different computer models of the climate system and measurements from the satellite-based Special Sensor Microwave Imager (SSM/I), atmospheric scientists from LLNL and eight other international research centers have shown that the recent increase in moisture content over the bulk of the world's oceans is not due to solar forcing or gradual recovery from the 1991 eruption of Mount Pinatubo. The primary driver of this 'atmospheric moistening' is the increase in carbon dioxide caused by the burning of fossil fuels.

"This is the first identification of a human fingerprint on the amount of water vapor in the atmosphere," Santer said.

"Fingerprint" studies seek to identify the causes of recent climate change and involve rigorous comparisons of modeled and observed climate change patterns. To date, most fingerprint studies have focused on temperature changes at the Earth's surface, in the free atmosphere, or in the oceans, or have considered variables whose behavior is directly related to changes in atmospheric temperature.

snip

Q4: Does our work have any larger implications"

Yes

One persistent criticism of the "discernible human influence" findings of previous IPCC assessments is that such conclusions were largely based on "fingerprint" studies which relied heavily on surface temperature changes. The thrust of the criticism was this:

"If there really is a signal of human activities lurking in the climate system, it should be manifest in many different climate variables, and not in surface temperature alone".

Our study helps to refute this criticism, and shows that we have now moved well beyond "temperature only" fingerprint studies.

end of excerpt. Bolding my emphasis.

and breeding.

If water vapor is increasing why is drought getting worse?

While its informative to use an average, it's definitely not new knowledge that warm air holds more moisture than cold air. So, when the increased water vapor cools, say as a result of updraft or vertical velocity (where pressure decreases: cools as a result of expansion), why isn't there more precipitation?

Summary questions: Who's lying? Or, Where's the rain?

Floods and excessive rain are prevalent now in many parts of Africa, India, and Asia in general. I believe it is because of the shifts in the jet stream as well that weather patterns are also being affected as in areas used to little rain getting much more and vice versa. And the effect of increased heat in the atmosphere would also cause more rapid water evaporation in parts of the world experiencing more warming.

...and not falling out. Which would be the definition of increased water content in the air.

I don't see any inconsistency.

You haven't noticed all the SEVERE flooding events in recent years???

Some places are getting NONE, and others are getting way too much, and at the wrong times.

Nobody ever claimed any particular location would get consistently more rainfall.

It's all about CLIMATE DESTABILIZATION and increased unpredictability. The models are all broken now.

What these scientists are talking about is an uptrend in average water content globally, and is a much, much smaller amount of water than we see as rain. You'll also note that the scientifically illiterate journalist or editor managed to screw up this article by changing "square meters" to "cubic meters" and in the process, thankfully but also as an extra flourish of ignorance, forgot to change the m² to m³. Obviously a cubic meter of air does not contain kilograms of water vapor, they are talking about the amount in the air column "over" a square meter or ground.

From wiki:



(25mm of rain on a square meter is 2.5Kg, which is in line with a 2% per year increase meaning about half a Kg per decade.)

it can be X feet in height, the higher one goes, the lower the pressure, until "space" is reached. It follows that there is a total, finite amount of "air" in the sky above us, that relates to X, and that further is presumably increasing as liquid crude is turned into a gas. So, the total volume of Air, lets call that A. (the actual volume calculation would be a large sphere minus a smaller sphere (the earth), but to avoid the weeds, just call it A)

I haven't seen a chart of A expressed over time anywhere. Does it exist anywhere? It stands to some reason that if A is increasing, there would be more water vapor held in the column.

Air is made up of 78% nitrogen 21% oxygen, under 1% carbon dioxide.

In order to accommodate a 1% to 3% per year increase in water content simply by expanding the atmosphere, if we were only adding CO2, we'd have to more than double it every year. So this is just simply not why.

they seem to normalize for total volume and only indicate relative increases.

The greenhouse effect was misnamed. It should have been called the balloon effect. Greenhouses are fixed in size. The atmosphere is not.

Further, CO2 cannot be the only gas added by expanding crude into a gas. It's easy to focus on when looking at relative changes which obscure total changes.

Percentages in this case are molar, not by volume. In addition, the "height" of the atmosphere is determined not by how much gas there is, but by how much gas the gravity of the earth can keep from escaping into outer space. I'm afraid your theory doesn't hold water.

There are trace gases that are produced by fossil fuel burning. Compared to CO2, though they are nothing when it comes to gas volume. "Perfect" combustion of gasoline or diesel releases only CO2 and water vapor, and ICEs are pretty darn close to perfect in this respect these days.

On average the clouds seem higher than they were 40 years ago. I'm not claiming this is a scientific observation, just what I've seen. In the last decade, I've also seen more rains from a distance from these same 'higher clouds' that appear to evaporate before hitting the ground.

Is it your claim that over a long time, even geologic and glacial time periods, the earth's atmosphere has not changed height? That even though the relative gases comprising it are thought to have changed, that the total amount of gases have remained relatively constant and are fixed by the earth's gravity?

Then why would clouds, on average and non-scientifically, appear higher in as short a time period as a single lifetime? Is it some kind of optical illusion?

You are not imagining things:

http://en.wikipedia.org/wiki/Noctilucent_clouds

However as to the height of the atmosphere itself, it would take a drastic change in composition for the height of the layers to change, not the 1% or less gasses like CO2, you'd actually have to have a change in the concentration of nitrogen and oxygen. We've had about the same levels of oxygen and nitrogen for about 200 million years.

part before we achieve a new (and probably drastically different) steady state.

Be afraid.

Be very afraid.

And by all means, keep wasting energy, 'cause it's just my imagination....

So sayeth the climate skeptics and their benefactors who get rich off lying to us.

...if you collect your own power at your own home, you don't need them or their filthy companies, and they can't get rich selling you watt hours.

Reason enough to strive for personal (or small-community) energy independence in my mind.

because the power IS in our hands and they know it.

the Colorado river basin.
downwind of Lake Nasser - Nile river, same

aircraft humifify the formerly dry upper atmosphere
.
none of the above,
implies precipitation localy

increasing the relative humidity
of the air in a desert from zero to 20 percent,
does not change the desert into a rain forest