WTF?

Almost all the general population and most of those who talk about climate change and melting ice-sheets miss what I consider to be the most important scientific concept.

Most people believe that ice melts slowly and consistently – it does not.
Ice at 0º will absorb enormous amounts of heat energy and remain at 0º and remain ice.
Then with little warning it will turn to water extremely quickly.

The ice melts at the moment are the result of localised interactions between the ice surface and the atmosphere. We have no way of knowing how much heat has already been absorbed.

Climate change denialists find the concept of latent heat either incomprehensible or too confronting.

When the tipping point for ice melting is reached nothing humans can do will stop it.

Sufficient fresh water for food production will be the next boundary crossed.

According to my reckoning, the specific heat of ice is approximately half that of water, so that if the body of ice is absorbing a lot of heat before it melts then its temperature must have been somewhat below its melting point, something which I presume those interested could fairly easily measure.

Let me give an exampe of what might actually happens.

If you start with a gram of ice which is at a temperature of -10 derees Celsius, it will then take 5 calories of heat to raise its temperature to 0 degrees. To melt that ice will take another 40 calories, (the latent heat of fusion) the temperature remaining at 0 degrees, but it doesn't just suddenly melt. After you have put in 20 calories, 0.5 grams of ice will remain and there will be 0.5 grams of water. If you then add another 20 calories of heat, the temperature of the remaining 1 gram of water will still be at 0 degrees. Adding a further 10 calories will then raise the temperature of that water to 10 degrees Celsius.

It might have been 60 years since I studied physics, but I don't think that has changed.

David

Now for our second lesson in physics for the day. Something that the AGW sceptics and deniers might need to consider.

Looking at global temperatures, you might consider what the current effect of the great masses of ice at the poles is having on the mean temperature of the earth. As with the above example, while the ice is still melting, the mean temperature remains constant. After the ice has all gone, there is no ice remaining to regulate the temperature.

All might not be lost however. There is still a great mass of ocean and its effectiveness at regulating temperature is about 13.5 times that of ice in tha instead of taking 40 calories to convert one gram of ice into water, it takes 540 calories to convert one gram of water into water vapour so we might find that in due course, the climate feels a little more tropical as the atmospheric humidity rises.

That is my lot for the day.

David

thank you VK3AUU for those precise physics examples. So that's probably where the expression 'tipping point' came from. But we pedestrians still believe in 'gradual' evolution, but I'll bet London to a brick that catastrophic evolution is probably a lot closer to the way nature really works with humans interacting, and volcanoes, tsunamis and floods par for the course.

As Mark Twain put it, 'We expect climate, but get weather instead."

Philip Ball's book "critical mass" speaks of the above as 'critical Phase transmissions' essentially he describes the process in historical perspective and atomic context. It explains the comparative suddenness of this phase transition from ice to liquid.
pages 40-49
It good for those who aren't particularly versed in physics.(like me)
Logically, I see no reason why some of these so called boundaries aren't in essence the same critical phase transmissions only on a hugely larger scale.

I do wonder however if there might not be linkages i.e. one tipping point contributes others at or by different amounts and rates.

another global warning hit peace...<<Over the past..10,000 years,..as our ancestors invented agriculture and built cities,..the Earth remained relatively stable.>>>that is a big clue...little wonder its been balancing itself for billions of years

<<The average global temperature fluttered slightly,>>>define slightly>>..never lurching towards a greenhouse climate or chilling enough to enter a new Ice Age.>>>..unless the sun is in its long DISTANT/orbit..and AS distance varies..WE FLUCTUATE..like when europe froze over briefly 500 years ago...

now thats a sure sign...
currently they barely get snow,..go figure eh?

NEXT...LOL..<<The pH of the oceans remained steady..providing the right chemical conditions...for coral reefs to grow and invertebrates to build shells.>>>YES PH IS A FUNNY THING...

TO0 much ACID...and calcium disolves into the water...neutralising the acidity...lol...ie self healing...get it?

<<Those species,..>>>loose definition...inverabrates are not at the species level...but what else is to be expected..from/by a puff piece on climate warning

those genus/containing species..each within their genus..<<in turn,..helped support a stable food web that provided plenty of fish for us humans to catch.>>>thats sort of the point...

ITS OVER FISHING...that threatens the fish...specificlly allowing fopols/idioots/and retards to murder the breeding stock....their photos; are in the paper/criminals proud of killing the big breeders

<<The overall stability of the past 10,000 years>>>is self evident proof nothing man did change buckiss

<<may have played a big part in humanity’s explosion>>just as the new tax will explode the finance idiocracy..selfis-autocracy..for their next round on bonuses..on carbon credit's speculating and trading

<<<Now,ironically,..civilisation>>>read the banking cartel/lawyer/big business elites..<<have become so powerful..that it can reshape the>>next big indiustrial evolution..

as we destroy that..we killed the earth,..to build...
only to now do it all over AGAIN...

industry went broke doing it last time..

its time we had industry stasis...

reuse...not rebuild...
reuse...not recycle...
reuse...not rebut...

live...not/con-sume...subsume...
meet/thy need..not that..thy greed be met