Well you deserve many gold stars for the question, Trevor. My views on that come from more than one influence. I certainly believe that Global Warming has the potential to kill me, and everyone, and do it in my lifetime. That's not a view I hold because somebody told it to me. I was a teenager there were several environmental predictions, any one of which would have resulted in me being dead before I was 40. Global Warming was not on that list. I didn't become depressed, but my decision making was certainly affected. However, as I watched events unfold I saw that concerned citizens could make a difference if they got together and acted. The government fought those efforts as they now fight actions that would help with this problem. Still we eventually did get a Clean Air Act, a Clean Water Act, laws regulating the disposal of toxic wastes, and regulating the use and handling of nuclear materials. Diluted and ameliorated as these pieces of legislation were, they had enormous effect. To my surprise, I was doing fine when I turned 40. A lot of other people died during the long battles to get those laws. From their perspective, the predictions were right. Ask the families of the former residents of Love Canal, for example.
These events changed how I view predictions. The people making those predictions had no computers or satellites originally. As those things were acquired it not only showed the predictions were right, but the situation was worse than they thought. They also showed when our efforts began to bring about improvement. These technolgies also brought to light problems that would probably not have been discovered otherwise, like the ozone hole. The lesson of that was that predictions are not set in stone, and can be greatly affected by people, and that politics control that part of things. It also confirmed my belief that I would have been dead 20 years ago if we had continued doing things as we had, including the rate at which things were increasing.
I first encountered Global warming in my astronomy books. They recounted how the earth and Venus would have the same surface temperatures, if their atmospheres were the same. The composition of the planets was not different, but most of the carbon on Venus existed as gas in the atmosphere, and on earth it was mostly in solid and liquid forms. Venus had a surface temperature hot enough to melt lead, while earth had one moderate enough for life. As time went by, discoveries showed that the development of plant life in the oceans was the thing that changed earth's atmosphere, which was originally the same. The reason why that happened here, but not on Venus was thought to be various influences of the gravity of the Moon. Nobody specifically said that you me, or even jello would die if the earth's atmosphere became like that of Venus, I came to that conclusion myself.
Everywhere I have read or heard of this being discussed in the 50 years since, it's always been noted that converting the liquid and solid forms of Carbon back to gas could be expected to heat things up (beyond natural cycles), and that the measured levels of gaseous carbon have risen since the beginning of industrialization. They also stated that there was a point at which the rise in temperature could not be reversed, regardless of human actions, and that probably something would need to be done to prevent reaching that point.
Their best estimate was that Global Warming would become an issue in about 500 years. This was also their prediction as to the time frame when supplies of coal, oil and gas would become a concern. At that time, those things were available, conveniently near the surface right within our own borders.
The scientist based their predictions on prevailing conditions at the time. They did not speculate about changes that might occur. An appreciation of the intrinsic nature of that with any prediction is part of a scientific viewpoint. They did not predict or expect that we would rapidly move to 2 and 3 car families. They did not predict that the public transportation systems of most big cities would be torn out so that more cars, oil and gas could be sold. They did not include in their calculations that when the only fossil fuels remaining to convert to carbon gas were in inconvenient remote locations the amount of fossil fuel we would have to convert to carbon gas to get them and bring them here would be greater. They did not predict or expect that we would develop methods to drill and mine deposits deeper than anything imagined in their day, so they too could be converted into carbon gas. They did not imagine or predict the computer industry, and the many billions of tons of additional carbon that would be converted to gas to make and run it. Neither did they imagine Playstations, iPods, cell phones, homes with numerous television sets or any of the other things that kept adding to the gasification of the earth's carbon. Most importantly, they did not take into account that at the time there were around a dozen industrialized nations, by now all nations are in some state of industrialization. I think there were tacit assumptions like that we would have done more on alternate power sources and emission reduction. Now, no scientist told me, it was my own conclusion that each of these events moved that 500 year day of reckoning a little closer to the present time. I didn't read it somewhere, or see it on TV.
The originally expected scenerio was that we would run out of fossil fuels before the melting of the polar and glacial ice began, as that would signal the beginning of the end. No one considered the improved methods for mining and drilling, or the new goods and services and the additional carbon that would be converted to gas to make and maintain them. I watched the price of gasoline in America rise from 12-17 cents, then saw it suddenly shoot up to 50 cents, and the panic and long lines at the gas pumps that resulted. Experts predicted we would one day be paying as much as a dollar. Most Americans were outraged, but the rest of the world was already paying 4 dollars. We passed $1.50 in less than a year. I was pretty sure then that we would reach equilibrium with the rest of the planet, and we almost have.
The polar and glacial ice was noted to be melting about 5 years ago. This amounts to changes in it's seasonal adnce and retreat, so that less remains every year. The south polar cap has been stable in more or less it's current form sice the continents formed. It's been unaffected by the dozen or so ice ages and subsequent melts. At it's current rate, it'll be gone in 50 years or less. All that ice works like ice cubes in a drink. On a hot day, the drink doesn't heat until all the ice cubes are melted. then it goes right up.
If you look around you'll see estimates of the time to complete the melting process ranging from 150 years to about 40. You'll also notice that there is a difference in figures of this type based on whether they are from last year, last month, or yesterday. It's not hard to find a 20 year old paper that confidently states it won't even start for a thousand years.
Most of the huge discrepancy between the predictions and the actual events can be explained by the factors not included in the older predictions. It is not hard to look around and find numerous factors not being included right now. Things like the rate of new industrialization, and the decrease in the moderating effect of the polar ice as the polar ice disappears.are important factors. The most obvious thing is that although the events predicted are accurate, in every case they happen sooner than predicted, and predicted events move closer to the present time every day.
If these things continue as they are now, there should be no doubt that the final stages of the climate change will be upon us within our lifetimes, or shortly after. Nobody told me that either. Whether this can be changed depends on whether the death grip the current policy makers in the USA and Saudi Arabia have on the decision making process.
I'm not ready to concede that it's hopeless, and give up to these kinds of people without a fight. If we are not to survive the perhaps we can have a better quality of life in the remaining time than we would have if we take no action. I believe strongly in the old saying, "fortune favors the prepared".
I apologize for the length of this. It was unavoidable in this case.