I am trained in science, admittedly medicine, not climate science but I have been a close observer of this science for several decades and am terrified of the callous disregard most have of the worst disaster to fall upon mankind.
Since I feel that science has made its case for Global Warming (Global Climate Change) and for the effect humans have in its cause I was somewhat surprised when I received the following email frim a close friend whom I consider the be bright and with an open mind:
What is your best guess, do we have global warming, or are/were we in a warming cycle that is going to shift now to a cool down cycle for several years/decades?
I am an amateur in this branch of science and replied to him because I felt that it is critical for him and all the rest of us to have at least a basic idea of what this is all about. I don't guarantee that my emphasis is completely correct or that I haven't made some minor errors. I hope experts in climate science will realize that my motive is to educate a large portion of our society who still think this is all up in the air. It is not! If my friend whom I have a high regard is misinformed and under informed I assume that most non-scientists are also. My reply follows:
There is no doubt that we have global warming caused by human hydrocarbon use! Climate scientists have warned us for decades but the seriousness and speed are now becoming apparent to all but the Flat Earth Society. There are two basic concerns.
A. Global warming is easy to prove and the data is available for all who care. Virtually all countries have had accurate temperature recording for a hundred years. I f you were to record all the measurements, typically taken, say every 2 hours, add them all together for a year and divide by the number of measurements one will end up with the yearly average global temperature.
This is just third grade arithmetic. Do this yearly and a steady rise in temperature is clearly apparent. The rise is much, much greater than natural cycles over the same time. Nature requires hundreds to thousands of years to do what has happened since the beginning of the industrial age. A person of the Flat Earth mentality will have a problem since they believe the Earth has been around 6000 years rather than the 4.5 million years known to science.
B. The second part relates to the cause. As temperature changes are simple science to prove, it is also easy to calculate the human addition of carbon into the atmosphere and oceans over the same time by measuring the output from local sources and combining for the whole Earth; again simple math and science. In addition chemical measurements of atmospheric and ocean hydrocarbons is an easy measurement. The results show a rise that tracks almost exactly the rise in temperature. and this rise is many times that over ancient history.
Now if you are a "gut" scientist you will say , "how do they know what the CO2, , CO and CH3 levels were a thousand or ten thousand years ago." If you are a scientist you will look at air frozen in bubbles in glaciers and it has been determined that previously CO2 and the other gasses were less, and that changes take thousands of years not the hundred or so we are dealing with now.
In addition, carbon dioxide dissolves in water to produce carbonic acid and the amount has lowered the pH of the oceans and guess what, this also tracks the temperature, atmospheric carbon and temperature rise exactly and this change has happened over the same short period of time on a human time scale, not a geologic one.
These two items when looked at with supporting data, not wild guesses, show that there is real global warming (global climate change) and that the change is following that of measurable human activity. These two facts are not in debate among virtually all scientists.
There is much more to the story and it relates to predictions, and what can be done as well as some effects that many may not realize that are actually speeding the change.
1. Much of the natural cooling is from the reflection of heat off the ice in polar regions. When this melts as it has in Arctic summers and to a lesser degree in Antarctica it reveals dark seawater that absorbs heat accelerating the temperature climb. As permafrost melts in the extreme latitudes it allows release of methane that is trapped in permafrost. Methane is the most potent greenhouse gas. The summer melting of the Earth is something new and is speeding up warming.
2. There are other mechanisms including changes in heat transfer by ocean currents that are being altered to a major degree by warming. I won't go into all the mechanism but it is related to the addition of melted fresh water from ice sheet melting. One example is that the Gulf Stream is much weaker than just a few years ago. The Gulf Stream is what transfers heat from the equatorial areas to the north. Similar patterns occur in the Southern hemisphere and rest of the Northern hemisphere.
The result of this seems paradoxical and will cause Maine, Nova Scotia, Ireland and the UK to be colder. The UK and Ireland are at parallels near that of Moscow but thanks to the Gulf Stream have had pretty balmy weather.
3. Weather is driven by atmospheric heat and moisture. The more of each the more violent are the weather extremes. In all natural systems there is some daily and seasonal variability. I'm not talking about cycles, but the statistical variability of complex systems. That is why the temperature climb is more sawtoothed even though the overall trend is up.
4. I won't go into more detail, first because I am not a climatologist but I have offered enough information, all of which is confirmable with a few minutes on the net, but because I have presented plenty of information to allow anyone to see that Global Climate Change is real. If this is not enough just look ate the extremes of weather we have been seeing over the past few decades.
Don't confuse weather with climate even though they are related. The misinformed, most of whom seem to be of the Republican persuasion but other IQ challenged people and those too lazy to get educated do this all the time. The famous fool, Sen. James Imhofe from the enlightened state of Oklahoma, is often heard spouting his version of unscientific misinformation where he confuses the statistical weather variation as proof that Global Climate Change is not real. He and others like him are so handicapped that I doubt they can be convinced. The old saying, "don't confuse me with facts, my mind is made up" applies. Hopefully most citizens are brighter and better based in high school science.
In the space of a few years we have seen unusually hot weather, unusually cold weather, unusually dry weather, unusually wet weather. There have been bigger storms, floods, records broken daily. Surely this is enough to make anyone stop and at least consider that something is not right. Our paradoxical cold and snow in the Central US may be because of Arctic heating. Remember warming air in the Arctic will still be very cold to us humans.
Global Climate Change is the most serious challenge to higher life on Earth since the rise of humans. It certainly is closer and more serious than the chance of an asteroid striking Earth in the next 100 years.
People, usually wealthy business people like the Koch Brothers and G.W. Bush complain that cleaning up our carbon pollution will be too expensive. Try considering the cost of coastal flooding of cities around the World, cities like New York, San Diego, Norfolk, Miami, Venice Sidney etc. The cost of inaction is the devastatingly expensive option.
Since there is a delay between time of action and climate effect even if carbon pollution were to stop today the problem will advance for around thirty years before reversal. Because of the vicious cycle of permafrost hydrocarbon release and loss of reflective snow and ice there will certainly be a point of no return when the changes will accelerate and much of the planet will not be able to support food production and life.
I advise all to become educated. There is plenty of information on the net and in popular journals such as, "Scientific American" and The New Scientist."