Another feedback

[Vergent]

Warming Climate Sees Tundra Turn to Forest

http://www.scienceda...20606113146.htm

[blizzard1024]

Warming Climate Sees Tundra Turn to Forest

http://www.scienceda...20606113146.htm

I would love to see a study that takes the forest cover in the eastern U.S 100 years ago

vs. today's forest cover and if that makes a difference in the regional climate...especially

in winter. A regional GCM could be run with changing just the landuse conditions. This would

be very interesting to see if there is any difference in climate (without changing CO2).

100-150 years ago much of NY and PA was lumbered off completely. Pictures of the turn

of last century in central NY/northern PA showed bare hillsides...fields and farms with very few trees.

I have noticed when there is snow in the midwest, the visible satellite is noticeable

whiter than when there is fresh snow cover in the east. Our forests have come

back and certainly this has changed the albedo in winter.

In addition, trees I believe have more evapo-transpiration than fields(I am not 100% sure

on this as I vaguely remember reading this years ago). So are summers

cloudier and wetter in the east from just land use changes?? Could this

be the reason the 1910s-1930s had so many extremes...very hot extreme temperatures in

summer which we don't see anymore...and really frigid temperatures in the winter?

Again I am talking about the east only where forest cover has come back dramatically.

If you look at the state max and mins records, there are states in the northeast with record

maximums above or close to 110F from 80-100 years ago...you just don't see that

kind of heat anymore even with increased CO2. Likewise...the mins are not as extreme either

(could that be both CO2 and albedo??).

[Jonger]

I would love to see a study that takes the forest cover in the eastern U.S 100 years ago

vs. today's forest cover and if that makes a difference in the regional climate...especially

in winter. A regional GCM could be run with changing just the landuse conditions. This would

be very interesting to see if there is any difference in climate (without changing CO2).

100-150 years ago much of NY and PA was lumbered off completely. Pictures of the turn

of last century in central NY/northern PA showed bare hillsides...fields and farms with very few trees.

I have noticed when there is snow in the midwest, the visible satellite is noticeable

whiter than when there is fresh snow cover in the east. Our forests have come

back and certainly this has changed the albedo in winter.

In addition, trees I believe have more evapo-transpiration than fields(I am not 100% sure

on this as I vaguely remember reading this years ago). So are summers

cloudier and wetter in the east from just land use changes?? Could this

be the reason the 1910s-1930s had so many extremes...very hot extreme temperatures in

summer which we don't see anymore...and really frigid temperatures in the winter?

Again I am talking about the east only where forest cover has come back dramatically.

If you look at the state max and mins records, there are states in the northeast with record

maximums above or close to 110F from 80-100 years ago...you just don't see that

kind of heat anymore even with increased CO2. Likewise...the mins are not as extreme either

(could that be both CO2 and albedo??).

It probably does have a significant effect.... It will be dismissed as insignificant by the crowd here, count on it.

[Vergent]

I would love to see a study that takes the forest cover in the eastern U.S 100 years ago

vs. today's forest cover and if that makes a difference in the regional climate...especially

in winter. A regional GCM could be run with changing just the landuse conditions. This would

be very interesting to see if there is any difference in climate (without changing CO2).

100-150 years ago much of NY and PA was lumbered off completely. Pictures of the turn

of last century in central NY/northern PA showed bare hillsides...fields and farms with very few trees.

I have noticed when there is snow in the midwest, the visible satellite is noticeable

whiter than when there is fresh snow cover in the east. Our forests have come

back and certainly this has changed the albedo in winter.

In addition, trees I believe have more evapo-transpiration than fields(I am not 100% sure

on this as I vaguely remember reading this years ago). So are summers

cloudier and wetter in the east from just land use changes?? Could this

be the reason the 1910s-1930s had so many extremes...very hot extreme temperatures in

summer which we don't see anymore...and really frigid temperatures in the winter?

Again I am talking about the east only where forest cover has come back dramatically.

If you look at the state max and mins records, there are states in the northeast with record

maximums above or close to 110F from 80-100 years ago...you just don't see that

kind of heat anymore even with increased CO2. Likewise...the mins are not as extreme either

(could that be both CO2 and albedo??).

Hard to imagine the NE with no trees. Valid points, no, sound points! It explains why we have several Mets from the NE who are if not deniers, BAU foot draggers. They look at those high temps from the 30s, but forget that human activity can be highly negative forcing locally. There is going to be a big difference in a station surrounded by forest and one in an open field for miles around.

You have to add photosynthesis to the energy balance in summer.

One last point. The arctic shrubs/trees are in a very arid environment <250mm percip/year for the most part. They have no need to cool themselves. These plants will be very stingy with evaporation. Not true in the NE.

[skierinvermont]

It probably does have a significant effect.... It will be dismissed as insignificant by the crowd here, count on it.

The IPCC has a whole section on land use changes and albedo. Read it and get back to us.

[bgmsnowman]

I would think that a big reason that we are less prone to seeing very high temperatures in the summer in the northeast compared to the 1930s, is that many official temperature readings in the 1930s were taken in downtown areas, many on federal building roof-tops. The result was a partially fictional cooling trend from the 1930s to the 1960s, as stations were moved out to cooler airports on the outskirst of the cities.

[Vergent]

I would think that a big reason that we are less prone to seeing very high temperatures in the summer in the northeast compared to the 1930s, is that many official temperature readings in the 1930s were taken in downtown areas, many on federal building roof-tops. The result was a partially fictional cooling trend from the 1930s to the 1960s, as stations were moved out to cooler airports on the outskirst of the cities.

BGM,

Welcome to Americanwx

Vergent

[WeatherRusty]

I would love to see a study that takes the forest cover in the eastern U.S 100 years ago

vs. today's forest cover and if that makes a difference in the regional climate...especially

in winter. A regional GCM could be run with changing just the landuse conditions. This would

be very interesting to see if there is any difference in climate (without changing CO2).

100-150 years ago much of NY and PA was lumbered off completely. Pictures of the turn

of last century in central NY/northern PA showed bare hillsides...fields and farms with very few trees.

I have noticed when there is snow in the midwest, the visible satellite is noticeable

whiter than when there is fresh snow cover in the east. Our forests have come

back and certainly this has changed the albedo in winter.

In addition, trees I believe have more evapo-transpiration than fields(I am not 100% sure

on this as I vaguely remember reading this years ago). So are summers

cloudier and wetter in the east from just land use changes?? Could this

be the reason the 1910s-1930s had so many extremes...very hot extreme temperatures in

summer which we don't see anymore...and really frigid temperatures in the winter?

Again I am talking about the east only where forest cover has come back dramatically.

If you look at the state max and mins records, there are states in the northeast with record

maximums above or close to 110F from 80-100 years ago...you just don't see that

kind of heat anymore even with increased CO2. Likewise...the mins are not as extreme either

(could that be both CO2 and albedo??).

Global land use changes such a deforestation, particularly in the tropic are believed to contribute about 20% to the growing enhancement to the greenhouse effect and radiative forcing of climate.

[The_Global_Warmer]

I would think that a big reason that we are less prone to seeing very high temperatures in the summer in the northeast compared to the 1930s, is that many official temperature readings in the 1930s were taken in downtown areas, many on federal building roof-tops. The result was a partially fictional cooling trend from the 1930s to the 1960s, as stations were moved out to cooler airports on the outskirst of the cities.

This is more than a NE issue.Same thing in St. Louis, Pre-1960s.

[JBG]

Hard to imagine the NE with no trees. Valid points, no, sound points! It explains why we have several Mets from the NE who are if not deniers, BAU foot draggers. They look at those high temps from the 30s, but forget that human activity can be highly negative forcing locally. There is going to be a big difference in a station surrounded by forest and one in an open field for miles around.

You have to add photosynthesis to the energy balance in summer.

One last point. The arctic shrubs/trees are in a very arid environment <250mm percip/year for the most part. They have no need to cool themselves. These plants will be very stingy with evaporation. Not true in the NE.

I know anecdotally that a major wilderness area near I-84 and Route 9 near Fishkill was denuded around that time and is now densely forested. And we know that much of Vermont was farmed at the time of the Revolution and is now deep wilderness.

[Jonger]

I know anecdotally that a major wilderness area near I-84 and Route 9 near Fishkill was denuded around that time and is now densely forested. And we know that much of Vermont was farmed at the time of the Revolution and is now deep wilderness.

 

Michigan was completely deforested in the late 1800's, but it was reforested in the 1940's. Most of Michigan north of the central part of the lower peninsula is solid forest.

[JBG]

Michigan was completely deforested in the late 1800's, but it was reforested in the 1940's. Most of Michigan north of the central part of the lower peninsula is solid forest.

I think this pattern is largely true outside of the major cities and "core" suburbs of megalopolis. Most of New Hampshire north of Concord, most of Massachusetts west of Worcester, most of Vermont, most of Maine, and even much of Connecticut is reforested. In New York once your'e out of Southern Westchester and southern Rockland forests predominate outside of course the upstate cities.