We had been talking a long time. You had started with a glass of
mostly ice plus a little water in front of you, and now it was mostly
water plus a little ice. If we had started with a thermometer, stirred a
little, and read it, the initial temperature would have been zero
degrees Celsius (32 degrees Fahrenheit), and the current temperature
would still be zero degrees Celsius (32 degrees Fahrenheit). Yes, the
same temperature, because in a stirred mixture of a liquid (water in
this case) and its solid (ice in this case), as long as some liquid is
left, removing heat (say by putting it in the freezer) changes liquid to
solid instead of changing temperature, and adding heat (say from a nice
warm room) changes solid (ice) to liquid (water) instead of changing
temperature. A physicist might say: Phase conversion trumps (has
precedence over) temperature change.
But this is not about your glass of ice water. It is about our planet, Planet Earth. Planet Earth can not be stirred. It is not nice and mixed like the ice water. But it has immense amounts of water, an awesome amount of ice, and air and water motion exchange heat back and forth between water and ice. A physicist would describe it as a buffered system. What this means is that the temperature is modified by the water/ice exchanges, so the temperature does not tell the true story. Also, taking the temperature of a planet is a bit of a challenge, and it is really hard to prove you did it right.
To take Planet Earth's temperature, you need to cover all the locations on sphere Earth, let's say every 10 degrees of longitude, and every 5 degrees of latitude, so 72 by 36 gives us 2592 points to cover. (Who gets to do the poles?) Then there is the high and the low. Say surface up to 30 meters, by 30 centimeter steps takes us to 259 200 temperatures, and for water, surface down to 30 meters by 30 centimeter steps, and we are at about 440 000 temperatures. Then there are all the hours of the day, because Planet Earth rotates, and all the days of the year, because Planet Earth goes around the Sun. Every fifteen minutes for a year gets you about 35 000, so we now have about 15 billion temperatures. If we do this for five or ten years, for some averaging, we end up with between 75 and 150 billion temperatures. That is a lot of data points. And we have not discussed high mountains or deep valleys.
Well fortunately there is a much simpler way, provided by mama nature herself. It is the same science which applied to the ice water drink. Keep an eye on the ice. If it grows, the glass is losing energy, and if it shrinks, the glass is gaining energy. Even more to the point, what concerns us is not primarily the energy, but rather the ice. You see, almost all of Planet Earth's major cities are built near water. (Before the gasoline-powered truck, you could move stuff by horse and wagon or by water.) Water was better. If that ice really melts, (and there is a lot of ice on Planet Earth) all those cities flood. You might want to review the New Orleans disaster.
So to recap here, the ice is melting, which means Planet Earth is gaining energy. Continued ice melt will flood most cities, and those of us who live in those cities view this as a bad thing. Why is Planet Earth gaining energy? That is for another article, but it really does not matter. If the Sun did it by over-revving, don't expect an apology or reparations from either the Sun or the Cosmos. If we humans did it by burning 50% of Planet Earth's oil, plus a lot of gas, coal, and wood in only 50 years, well, what is done is done. You can't stick the carbon chains back together. It is a bad thing and even if we did not cause it, we need to stop or even reverse it, but that is for another article.
But this is not about your glass of ice water. It is about our planet, Planet Earth. Planet Earth can not be stirred. It is not nice and mixed like the ice water. But it has immense amounts of water, an awesome amount of ice, and air and water motion exchange heat back and forth between water and ice. A physicist would describe it as a buffered system. What this means is that the temperature is modified by the water/ice exchanges, so the temperature does not tell the true story. Also, taking the temperature of a planet is a bit of a challenge, and it is really hard to prove you did it right.
To take Planet Earth's temperature, you need to cover all the locations on sphere Earth, let's say every 10 degrees of longitude, and every 5 degrees of latitude, so 72 by 36 gives us 2592 points to cover. (Who gets to do the poles?) Then there is the high and the low. Say surface up to 30 meters, by 30 centimeter steps takes us to 259 200 temperatures, and for water, surface down to 30 meters by 30 centimeter steps, and we are at about 440 000 temperatures. Then there are all the hours of the day, because Planet Earth rotates, and all the days of the year, because Planet Earth goes around the Sun. Every fifteen minutes for a year gets you about 35 000, so we now have about 15 billion temperatures. If we do this for five or ten years, for some averaging, we end up with between 75 and 150 billion temperatures. That is a lot of data points. And we have not discussed high mountains or deep valleys.
Well fortunately there is a much simpler way, provided by mama nature herself. It is the same science which applied to the ice water drink. Keep an eye on the ice. If it grows, the glass is losing energy, and if it shrinks, the glass is gaining energy. Even more to the point, what concerns us is not primarily the energy, but rather the ice. You see, almost all of Planet Earth's major cities are built near water. (Before the gasoline-powered truck, you could move stuff by horse and wagon or by water.) Water was better. If that ice really melts, (and there is a lot of ice on Planet Earth) all those cities flood. You might want to review the New Orleans disaster.
So to recap here, the ice is melting, which means Planet Earth is gaining energy. Continued ice melt will flood most cities, and those of us who live in those cities view this as a bad thing. Why is Planet Earth gaining energy? That is for another article, but it really does not matter. If the Sun did it by over-revving, don't expect an apology or reparations from either the Sun or the Cosmos. If we humans did it by burning 50% of Planet Earth's oil, plus a lot of gas, coal, and wood in only 50 years, well, what is done is done. You can't stick the carbon chains back together. It is a bad thing and even if we did not cause it, we need to stop or even reverse it, but that is for another article.
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