Okay

Best I not hit enter before posting some content.

http://www.youtube.com/watch?feature=player_embedded&v=vpTHi7O66pI

A 20 minute video from the recent TED conference.

how about just having less people?

SO, combining sibeen and wookiemeister’s ideas, we have a cannibalism program.

india added 180 million people in ten years

stop rewarding nations that can’t support themselves and population will fall accordingly

sibeen said:

A 20 minute video from the recent TED conference.

Can we have a 2 minute summary of his argument?

Instead of getting rid of cattle and sheep, as a method of helping land recover; we should be stocking at far higher rates, but making the herd move far more often.

This system mimics what used to happen with large herds of bison, antelope etc, and is what the ground is used to.

Thanks sibeen,

It sounds like it could be worth looking at, but from the bits I looked at he did seem to be over-selling it without a lot of firm evidence (but then that seems to be a TED requirement).

I wonder what effect changes in reflectivity of large areas of land have on the climate. (Actually I wonder this every time I fly out of Sydney and see all the light coloured cultivated land, with patches of much darker remnant bush-land).

Is land-clearing slowing down temperature increases in the short term, and what happens when there is no un-cleared land left?

sibeen said:

Instead of getting rid of cattle and sheep, as a method of helping land recover; we should be stocking at far higher rates, but making the herd move far more often.

This system mimics what used to happen with large herds of bison, antelope etc, and is what the ground is used to.

in America maybe.

The Rev Dodgson said:

Thanks sibeen,

It sounds like it could be worth looking at, but from the bits I looked at he did seem to be over-selling it without a lot of firm evidence (but then that seems to be a TED requirement).

I wonder what effect changes in reflectivity of large areas of land have on the climate. (Actually I wonder this every time I fly out of Sydney and see all the light coloured cultivated land, with patches of much darker remnant bush-land).

Is land-clearing slowing down temperature increases in the short term, and what happens when there is no un-cleared land left?

Land clearing should be increasing temperatures. short and long term.

roughbarked said:

The Rev Dodgson said:

Thanks sibeen,

It sounds like it could be worth looking at, but from the bits I looked at he did seem to be over-selling it without a lot of firm evidence (but then that seems to be a TED requirement).

I wonder what effect changes in reflectivity of large areas of land have on the climate. (Actually I wonder this every time I fly out of Sydney and see all the light coloured cultivated land, with patches of much darker remnant bush-land).

Is land-clearing slowing down temperature increases in the short term, and what happens when there is no un-cleared land left?

Land clearing should be increasing temperatures. short and long term.

How do you know this?

The Rev Dodgson said:

roughbarked said:

The Rev Dodgson said:

Thanks sibeen,

It sounds like it could be worth looking at, but from the bits I looked at he did seem to be over-selling it without a lot of firm evidence (but then that seems to be a TED requirement).

I wonder what effect changes in reflectivity of large areas of land have on the climate. (Actually I wonder this every time I fly out of Sydney and see all the light coloured cultivated land, with patches of much darker remnant bush-land).

Is land-clearing slowing down temperature increases in the short term, and what happens when there is no un-cleared land left?

Land clearing should be increasing temperatures. short and long term.

How do you know this?

Why don’t you try taking your shirt off and standing in the sun?

Cl

The reflectivity of crops and trees are about the same ~20-25% iirc.

The Rev Dodgson said:

roughbarked said:

The Rev Dodgson said:

Thanks sibeen,

It sounds like it could be worth looking at, but from the bits I looked at he did seem to be over-selling it without a lot of firm evidence (but then that seems to be a TED requirement).

I wonder what effect changes in reflectivity of large areas of land have on the climate. (Actually I wonder this every time I fly out of Sydney and see all the light coloured cultivated land, with patches of much darker remnant bush-land).

Is land-clearing slowing down temperature increases in the short term, and what happens when there is no un-cleared land left?

Land clearing should be increasing temperatures. short and long term.

How do you know this?

Probably not an illogical conclusion.

There are two factors at play here, absorption, during the day, and re-radiation at night. Vegetated land may be darker than cleared land and absorb more heat, but it is not as dense as dirt so could re-radiate all that heat at night while cleared land could potentially retain some.

wookiemeister said:

how about just having less people?

Fewer people or lesser people?

RichardC said:

wookiemeister said:

how about just having less people?

Fewer people or lesser people?

the real number of people on the earth is unknown, we talk about a mob or a crowd rather than a particular number

people are therefore a mass noun

hence

“less”

i wouldn’t use “lesser”

Carmen_Sandiego said:

The Rev Dodgson said:

roughbarked said:

Land clearing should be increasing temperatures. short and long term.

How do you know this?

Probably not an illogical conclusion.

There are two factors at play here, absorption, during the day, and re-radiation at night. Vegetated land may be darker than cleared land and absorb more heat, but it is not as dense as dirt so could re-radiate all that heat at night while cleared land could potentially retain some.

The way I see it, it is a simple balance between total energy in and total energy out, with the temperature changing to maintain that balance. Thus, increasing the visible absorbance will increase the temperature, while increasing the infrared (thermal) absorbance will decrease the temperature by increasing the thermally radiated energy (good absorbers are also good radiators, as required by the 2nd law of thermodynamics). Even if the energy absorbed is being converted to non-thermal energy (eg by plants), this energy will eventually be converted to heat unless it is permanently stored, thus making no difference in the long term.

KJW said:

Carmen_Sandiego said:

The Rev Dodgson said:

How do you know this?

Probably not an illogical conclusion.

There are two factors at play here, absorption, during the day, and re-radiation at night. Vegetated land may be darker than cleared land and absorb more heat, but it is not as dense as dirt so could re-radiate all that heat at night while cleared land could potentially retain some.

The way I see it, it is a simple balance between total energy in and total energy out, with the temperature changing to maintain that balance. Thus, increasing the visible absorbance will increase the temperature, while increasing the infrared (thermal) absorbance will decrease the temperature by increasing the thermally radiated energy (good absorbers are also good radiators, as required by the 2nd law of thermodynamics). Even if the energy absorbed is being converted to non-thermal energy (eg by plants), this energy will eventually be converted to heat unless it is permanently stored, thus making no difference in the long term.

Short answer is an increase in temperature. Long answer is sort of, possibly, maybe. It’s a bit more complex than just heat in vs heat out.

Old but good paper “here”: http://grads.iges.org/people/Shukla%27s%20Articles/1990/Amazonia%20deforestation.pdf/

Try again

http://grads.iges.org/people/Shukla%27s%20Articles/1990/Amazonia%20deforestation.pdf

roughbarked said:

The Rev Dodgson said:

roughbarked said:

Land clearing should be increasing temperatures. short and long term.

How do you know this?

Why don’t you try taking your shirt off and standing in the sun?

I might do that, but I don’t see what it has to do with the question.

Any chance of a straight reply to a straight question?

The Rev Dodgson said:

roughbarked said:

The Rev Dodgson said:

How do you know this?

Why don’t you try taking your shirt off and standing in the sun?

I might do that, but I don’t see what it has to do with the question.

Any chance of a straight reply to a straight question?

It was straight enough.. strip earth’s blanket and it is at the mercy of the sun.

roughbarked said:

The Rev Dodgson said:

roughbarked said:

Why don’t you try taking your shirt off and standing in the sun?

I might do that, but I don’t see what it has to do with the question.

Any chance of a straight reply to a straight question?

It was straight enough.. strip earth’s blanket and it is at the mercy of the sun.

But that doesn’t answer the question (neither does the link to the deforestation paper). Not much visible light is absorbed by the atmosphere, but almost all infra-red is absorbed; so if a large area of land starts to reflect more visible light the amount of absorbed energy will be reduced, and I would expect that to have a cooling effect on the climate, rather than warming.

The Rev Dodgson said:

roughbarked said:

The Rev Dodgson said:

I might do that, but I don’t see what it has to do with the question.

Any chance of a straight reply to a straight question?

It was straight enough.. strip earth’s blanket and it is at the mercy of the sun.

But that doesn’t answer the question (neither does the link to the deforestation paper). Not much visible light is absorbed by the atmosphere, but almost all infra-red is absorbed; so if a large area of land starts to reflect more visible light the amount of absorbed energy will be reduced, and I would expect that to have a cooling effect on the climate, rather than warming.

and what of the UV?

The Rev Dodgson said:

roughbarked said:

The Rev Dodgson said:

I might do that, but I don’t see what it has to do with the question.

Any chance of a straight reply to a straight question?

It was straight enough.. strip earth’s blanket and it is at the mercy of the sun.

But that doesn’t answer the question (neither does the link to the deforestation paper). Not much visible light is absorbed by the atmosphere, but almost all infra-red is absorbed; so if a large area of land starts to reflect more visible light the amount of absorbed energy will be reduced, and I would expect that to have a cooling effect on the climate, rather than warming.

Thank goodness for the Sahara desert then.

“and what of the UV?”

The energy that arrives at the surface of the Earth is that which hasn’t been absorbed by the atmosphere, so if the frequency isn’t changed much, not much will be absorbed on the way out either.

The Rev Dodgson said:

“and what of the UV?”

The energy that arrives at the surface of the Earth is that which hasn’t been absorbed by the atmosphere, so if the frequency isn’t changed much, not much will be absorbed on the way out either.

The trouble with your argument is that to reach the point, along the way we get to look like Mars.

roughbarked said:

It was straight enough.. strip earth’s blanket and it is at the mercy of the sun.

Blanket or no blanket, the earth intercepts the same amount of solar energy. What isn’t reflected is absorbed. While absorption in the upper atmosphere may not directly impact us here on the ground, I strongly suspect that increasing the absorption in the upper atmosphere will ultimately affect us here on the ground.

roughbarked said:

The Rev Dodgson said:

“and what of the UV?”

The energy that arrives at the surface of the Earth is that which hasn’t been absorbed by the atmosphere, so if the frequency isn’t changed much, not much will be absorbed on the way out either.

The trouble with your argument is that to reach the point, along the way we get to look like Mars.

To reach what point?

I’m just trying to get some information on the actual nett effect of land clearing, and the reason why it has that effect.

The Rev Dodgson said:

roughbarked said:

The Rev Dodgson said:

“and what of the UV?”

The energy that arrives at the surface of the Earth is that which hasn’t been absorbed by the atmosphere, so if the frequency isn’t changed much, not much will be absorbed on the way out either.

The trouble with your argument is that to reach the point, along the way we get to look like Mars.

To reach what point?

I’m just trying to get some information on the actual nett effect of land clearing, and the reason why it has that effect.

Well to begin to realise, removing the blanket affects the stability of the upper atmosphere that KJW is discussing.

mars looks the way it does because of lack of gravity not lack of vegetation.

Boris said:

mars looks the way it does because of lack of gravity not lack of vegetation.

But take the vegetation off and?

Deforestation has multiple effects. The change in the surface colour does increase the albedo, which is of course a cooling effect. However the wood that is cut down is almost always burned or rots, and this adds long-lived GHG into the atmosphere, producing a warming effect.

Deforestation also tends to reduce the water vapour content, but as discussed many times, on a global level this is compensated for by increased evaporation.

“Well to begin to realise, removing the blanket affects the stability of the upper atmosphere that KJW is discussing.”

What effect does it have on the stability of the upper atmosphere, how does this affect the climate in qualiative and quantative terms, how does this effect compare with the effect of the increased albedo, and how reliable are the investigations that have reached these conclusions?

The Rev Dodgson said:

“Well to begin to realise, removing the blanket affects the stability of the upper atmosphere that KJW is discussing.”

What effect does it have on the stability of the upper atmosphere, how does this affect the climate in qualiative and quantative terms, how does this effect compare with the effect of the increased albedo, and how reliable are the investigations that have reached these conclusions?

Ask Flannery, he must have blog somewhere.

But take the vegetation off and?

what? we’re talking mars here. did it have vegetation?

The Rev Dodgson said:

“Well to begin to realise, removing the blanket affects the stability of the upper atmosphere that KJW is discussing.”

What effect does it have on the stability of the upper atmosphere, how does this affect the climate in qualiative and quantative terms, how does this effect compare with the effect of the increased albedo, and how reliable are the investigations that have reached these conclusions?

Of these parts I clearly need to check against the known parameters before attempting to convince you but as a gut feeling.. I think we are here because of the fact that our atmosphere relies upon the blanket it creates.

Boris said:

But take the vegetation off and?

what? we’re talking mars here. did it have vegetation?

apparently it did once upon a time.

MartinB said:

Deforestation has multiple effects. The change in the surface colour does increase the albedo, which is of course a cooling effect. However the wood that is cut down is almost always burned or rots, and this adds long-lived GHG into the atmosphere, producing a warming effect.

Deforestation also tends to reduce the water vapour content, but as discussed many times, on a global level this is compensated for by increased evaporation.

The fate of the GHG is something else.

What I’m interested in is the nett direction and magnitude of the effect of the changed albedo. I’m also interested in why no-one talks about it much, but that’s another question (unless the answer is that no-one talks about it because it’s insignificant).

>apparently it did once upon a time.

Um, no.

apparently it did once upon a time.

there is no evidence that this is true. none.

The Rev Dodgson said:

MartinB said:

Deforestation has multiple effects. The change in the surface colour does increase the albedo, which is of course a cooling effect. However the wood that is cut down is almost always burned or rots, and this adds long-lived GHG into the atmosphere, producing a warming effect.

Deforestation also tends to reduce the water vapour content, but as discussed many times, on a global level this is compensated for by increased evaporation.

The fate of the GHG is something else.

What I’m interested in is the nett direction and magnitude of the effect of the changed albedo. I’m also interested in why no-one talks about it much, but that’s another question (unless the answer is that no-one talks about it because it’s insignificant).

I don’t think it is insignificant though I don’t have the science grounding to be an authority by any means.

Teleost said:

It’s a bit more complex than just heat in vs heat out.

Sometimes I think that people get bogged down by the complexity and overlook what is ultimately quite simple (can’t see the forest for the trees).

Boris said:

apparently it did once upon a time.

there is no evidence that this is true. none.

yeah .. but it does depend on much research yet to be forthcoming if we are still around to get there.

You not heard of the sweeping and majestic Martian forests?

KJW said:

Teleost said:

It’s a bit more complex than just heat in vs heat out.

Sometimes I think that people get bogged down by the complexity and overlook what is ultimately quite simple (can’t see the forest for the trees).

There is always that.

Skunkworks said:

You not heard of the sweeping and majestic Martian forests?

Cheech and Chong’s secret crop?

Anyway, if we really can save the planet by eating meat, I’d say that’s pretty damn good news.

(can’t see the forest for the trees)

what tress? what forest? we cut all them down about 15 posts ago. needed to burn them to keep the servers running so we could talk about global warming and stuff.

if you ask me i find that kinda ironic.

Boris said:

(can’t see the forest for the trees)

what tress? what forest? we cut all them down about 15 posts ago. needed to burn them to keep the servers running so we could talk about global warming and stuff.

:)

that could become a real issue without notice.

The Rev Dodgson said:

The fate of the GHG is something else.

What I’m interested in is the nett direction and magnitude of the effect of the changed albedo.

Ignoring the GHG component, deforestation leads to a cooling effect through albedo changes.

The Rev Dodgson said:

I’m also interested in why no-one talks about it much, but that’s another question (unless the answer is that no-one talks about it because it’s insignificant).

Well, ignoring GHG is not normally likely to give realistic results in understanding climate (although it can of course be a useful analytical technique).

But more to the point it is discussed, by the IPCC, specifically in section 2.5

Bubblecar said:

Anyway, if we really can save the planet by eating meat, I’d say that’s pretty damn good news.

You’re single-handedly keeping us going, ‘Car. :)

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

MartinB said:

Well, ignoring GHG is not normally likely to give realistic results in understanding climate (although it can of course be a useful analytical technique).

But more to the point it is discussed, by the IPCC, specifically in section 2.5

I wasn’t suggesting that GHG should be ignored, just that it should be separated from albedo effects.

Anyway, thanks for the link, from which it seems that albedo effects are highly uncertain, but may be of a similar magnitude to GHG emissions.

The Rev Dodgson said:

MartinB said:

Well, ignoring GHG is not normally likely to give realistic results in understanding climate (although it can of course be a useful analytical technique).

But more to the point it is discussed, by the IPCC, specifically in section 2.5

I wasn’t suggesting that GHG should be ignored, just that it should be separated from albedo effects.

Anyway, thanks for the link, from which it seems that albedo effects are highly uncertain, but may be of a similar magnitude to GHG emissions.

I do hope you’ll get back to us with your conclusions.

The Rev Dodgson said:

MartinB said:

Well, ignoring GHG is not normally likely to give realistic results in understanding climate (although it can of course be a useful analytical technique).

But more to the point it is discussed, by the IPCC, specifically in section 2.5

I wasn’t suggesting that GHG should be ignored, just that it should be separated from albedo effects.

Anyway, thanks for the link, from which it seems that albedo effects are highly uncertain, but may be of a similar magnitude to GHG emissions.

I do hope you’ll get back to us with your conclusions.

roughbarked said:

I do hope you’ll get back to us with your conclusions.

My conclusions are not worth a lot, since I’m very inexpert in this area, but for what they are worth, I have already posted them:

“Anyway, thanks for the link, from which it seems that albedo effects are highly uncertain, but may be of a similar magnitude to GHG emissions.”

The Rev Dodgson said:

roughbarked said:

I do hope you’ll get back to us with your conclusions.

My conclusions are not worth a lot, since I’m very inexpert in this area, but for what they are worth, I have already posted them:

“Anyway, thanks for the link, from which it seems that albedo effects are highly uncertain, but may be of a similar magnitude to GHG emissions.”

Or, to summarise, the science is not settled. ;-)

morrie said:

The Rev Dodgson said:

roughbarked said:

I do hope you’ll get back to us with your conclusions.

My conclusions are not worth a lot, since I’m very inexpert in this area, but for what they are worth, I have already posted them:

“Anyway, thanks for the link, from which it seems that albedo effects are highly uncertain, but may be of a similar magnitude to GHG emissions.”

Or, to summarise, the science is not settled. ;-)

or summat.

Science is never settled but the uncertainties involved do not justify dismissing the predictions of mainstream climatology.

MartinB said:

Science is never settled but the uncertainties involved do not justify dismissing the predictions of mainstream climatology.

who was doing that?

“the science is not settled” in my reading usually posits a false equivalence between mainstream climatology and minority climatology suggesting that the results of the mainstream science can be downplayed or disregarded. Yes I understand the comment had an emoticon.

MartinB said:

“the science is not settled” in my reading usually posits a false equivalence between mainstream climatology and minority climatology suggesting that the results of the mainstream science can be downplayed or disregarded. Yes I understand the comment had an emoticon.

as you were.