What's the perfect temperature for earth [poll]?

[Pmt111500]

As humans are currently considered a force of geologic proportions, let's try in the spirit of http://vvattsupwiththat.blogspot.fi/2014/03/somewhere-close-to-iq-of-guy-who-asked.html
to answer what's the perfect temperature of the earth  . Please consider all the effects a stable temperature of your selection will have in equilibrium. This of course assumes that the atmospheric and oceanic circulation, glacier meltdown (or build-up), sea level rise (or drop) have reached a stable state of the temperature selected. In order to get more varied results, please assume further that a stable civilization is still present. Describe the said civilization in comments, if willing. (experiment on futurology). I know there are people who like their living quarters to be constantly over 20 degrees Celsius, and the evenly spread scale ends at 20, but please note this is a Global value, including nights and winters.

[ccgwebmaster]

Not really sure why one would pick anything other than the pre-industrial Holocene average or some value reasonably close to it? It seemed to be working fine for us until we messed with it...

[Pmt111500]

people are sometimes selfish...

[crandles]

Please consider all the effects a stable temperature of your selection will have in equilibrium.

This could be difficult:

Greenland and Antarctica are losing mass at current temperature. If height is lost, rate of loss may increase so substantially all ice disappears. OTOH maybe warmer world deposits more snow.

There again losing most Greenland ice would make the world warmer so the rest of the world has to cool to maintain current temperature and that might allow Greenland ice to remain. So maybe current global average temperature is just not possible.

.

On a different line: Cold weather kills more people than hot weather so maybe we should want a warmer world. If that means Greenland and Antarctica melt there may be less land mass due to sea level rise. Is a smaller equilibrium population good or bad or irrelevant to the question so that fewer people dying due to cold makes this a sensible choice?

[JimD]

On a different line: Cold weather kills more people than hot weather so maybe we should want a warmer world. If that means Greenland and Antarctica melt there may be less land mass due to sea level rise. Is a smaller equilibrium population good or bad or irrelevant to the question so that fewer people dying due to cold makes this a sensible choice?

Crandles

I believe that the scientific answer is the hot weather kills more than cold weather has been proven.  The denier camp has made a small industry out of confusing this issue by playing with the statistics and setting their criteria on the wrong metrics.  The death rate is higher in the winter than the summer but it is not from the cold per say. 

Almost everyone who dies from heat or cold are the weaker members of society; i.e. the children and the old.  Recall the great European heat wave in 2003?.  Average numbers indicate that approximately 50,000 died from the heat.  An inconceivable number to die from a cold snap.  Having lived in places without air conditioning that hit temperatures of 110F I can say it is clear that heat will get you first.  One can add clothes and blankets to keep warm, but if you do not have AC and it is real hot there are limited things you can do (and if the humidity is high at the same time - look out).  Anyone can survive minus 40 C with some preparation.  If it lasts long enough no one can survive exposure to wet-bulb temperatures above 35C. 

http://www.lomborg-errors.dk/coolitBchap2heat.htm

http://www.wunderground.com/climate/heatmortality.asp

But all that being said, if my wife gets to pick the temperature we are all doomed!  She doesn't stop shivering until it is about 95F.

BTW isn't the average global temperature right now about 14.6 C?  20C would be the end of the world for most of us.

[crandles]

But is it true that so many die from cold? Only if you make a trick by including the normal seasonal variation in death rate. It has always been so, and will remain so, that more people die during the winter months than during the summer months. Old and seriously sick people have less vitality in the dark season. It is too bold to say that the excess deaths during the dark part of the year are `deaths due to excess cold´. There is no evidence that a warmer climate will alter the seasonal variation. These people would soon die in any case, even if winters became warmer. Indeed, cold and warm climates, like Finland and Greece, have aprroximately the same seasonal variation in mortality. Thus, the figures in the book for cold-related deaths lack sound foundation.

Interesting and sorry if I was spreading mis-information.

If "Old and seriously sick people have less vitality in the dark season." were a major reason then shouldn't you expect Finland to have higher winter mortality than Greece. If it doesn't, then doesn't this cast doubt on that alternative explanation?

I suspect it is a bit more complicated and care does need to be taken. It is probably temperature relative to what frail people are adequately prepared for rather than just temperature. Also damp conditions that assist spread of disease might be worse than temperature effects.

People being prepared for what is likely may well be ideal but that presumably applies to all equilibrium temperatures.

[OldLeatherneck]

I'd be more concerned about achieving climate equilibrium than an "ideal" global mean temperature.  Human beings have been able to adapt to living in very extreme temperature extremes from the Inuits in the Arctic to the Beduins in Arabia, not forgetting the aborigines in Amazonia an Australia.  With proper shelter and clothing, humans can survive and thrive in a broad range of temperature extremes.

Personally, I've lived and/or worked in some of these environments.  I finished elementary school and Junior High School, during the 50s, in Duluth Minnesota where the locals claimed they only had two seasons, Winter and August.  I also spent a winter working in Thule, Greenland.  At the other extreme, I've spent many summers in the Desert Southwest, including California, Nevada and Arizona.  Not to mention of course multiple trips to Saudi Arabia and Bahrain.

However, the aging process has changed my tolerance to the extremes of heat or cold.  Now, if I'm outdoors and the temperature is below 70^o(F) I want sunshine and if it's above 85^o(F) I want shade.

What I've noticed and struggled with this particular winter in the Hill Country of Texas is number of wild temperature swings from day to day or week to week.  As an example, my wife and I went to Austin to celebrate her birthday last weekend.  On Saturday evening we were walking the downtown streets in our shirtsleeves, not leaving the last jazz club until rather late.  The temperature was still in the 70s.  When we woke up Sunday morning the temps were in the 50s and by mid afternoon they had dropped into the 30s.  However,  the dramatic temperature drop in Lubbock, TX was much more extreme, with a high of 85^o(F) on March 1st and a low of 12^o(F) on march 2nd.

http://www.wunderground.com/history/airport/KLBB/2014/3/2/DailyHistory.html?req_city=NA&req_state=NA&req_statename=NA

These frequent signs af climate instability are more alarming to me the the actual changes to mean temperatures.

[JimD]

If "Old and seriously sick people have less vitality in the dark season." were a major reason then shouldn't you expect Finland to have higher winter mortality than Greece. If it doesn't, then doesn't this cast doubt on that alternative explanation?

I suspect it is a bit more complicated and care does need to be taken. It is probably temperature relative to what frail people are adequately prepared for rather than just temperature. Also damp conditions that assist spread of disease might be worse than temperature effects.

People being prepared for what is likely may well be ideal but that presumably applies to all equilibrium temperatures.

I agree that it is complicated.  Additional factors that impact winter to summer are psychological/physiological ones.  I have lived in Germany and Greece.  Even when the temperatures are comparable it is normally much nicer in Greece in the winter than Germany.  The same kind of thing occurs here in the US.  Where I lived in Virginia in the winter was actually warmer at night and about the same in the daytime as where I live now in Arizona.  Winters in AZ are much nicer.  Why?  Sunshine!  Places that are cloudy, damp, gloomy, darker in the winter are hard on ones mental state.  People are often depressed more in the winter, get less exercise, are cooped up inside, and such.  This makes one more prone to illness.  Especially dangerous to the old and young.  But the deaths caused by such things are not really due to cold temperatures in any sense comparable to what it is about heat that kills.  Sort of like comparing apples and oranges in a way.  Lots of people die when it is hot because they cannot cool themselves and this causes physical failure.  Very few people die from hypothermia or freezing.

One of the biggest problems with heat is that the very young do not yet have the ability to perspire effectively to help cool themselves and their internal temperature rises very fast if they are in excessive heat.  Quite a number of small children die each year in Arizona because an adult leaves them in the car for times as short as 30 mins.  On the other end of the scale as one passes from middle age into old age their body slowly looses its ability to regulate internal temperature via efficient perspiration (regressing to childhood I guess).   I notice that myself.  When I was young I ran around Africa and the Middle East in tremendously hot temperatures with little problem.  Now I sweat out very quickly compared to what I used to and have to be careful not to dehydrate.  If I overdue it the time it takes to recover is also much longer. 

[Shared Humanity]

Day time highs between the mid 70F and mid 80F. Night time lows around 55F. As soon as I find the place, I will retire there.

Oh! This isn't  what you meant? 

[icefest]

I think this proves that some people just want to watch the world burn.

Well, and flood and melt.

It's beginning to remind me of the far eastern curse: "May you live in interesting times."

[crandles]

I think this proves that some people just want to watch the world burn.

Well, and flood and melt.

It's beginning to remind me of the far eastern curse: "May you live in interesting times."

Not sure it "proves" anything of the sort. The question is just so far removed from reality of how to move towards a system that is nearer to being in equilibrium (if that is even a priority) that I don't think you can take any such message from the answers.

[ChasingIce]

Day time highs between the mid 70F and mid 80F. Night time lows around 55F. As soon as I find the place, I will retire there.

Oh! This isn't  what you meant? 

Sounds like you're looking for San Diego, CA.

[Rick Aster]

In a certain narrow economic sense, I would argue that the perfect temperature for humans on Earth is the average of the past lifetime because that is what people and infrastructure have adapted to. It is what we know, so it gives us the best chance to feed, clothe, and house people. There is an obvious problem with this approach, though. People would like to keep both the current temperature and the current sea level, and sea level is rising at current temperature. I doubt there could be a consensus to lower temperate enough to stop sea level rise.

[adelady]

Just for fun.   

http://www.care2.com/causes/top-10-places-in-the-world-for-beautiful-weather.html

http://science.howstuffworks.com/nature/climate-weather/atmospheric/10-countries-with-perfect-climates.htm#page=0

But all of these places rely on the "air conditioning" provided by frozen polar regions as well as prevailing winds, seasonal rains and all the rest of it.  So whatever global average temperature provides reliable growing seasons for crops and a range of livable climates for people with various preferences is the average we want.  (A lot of people would regard those "ideal" ten locations as great for a holiday but boring to live with year in year out.)