Estimating the interaction between the various Earth’s stressors as listed in yesterday’s post leaves me with the impression that there are various time scales upon which the various stressors operate. Three decades of projection is probably longer than makes sense for some of the things listed but not for others.
1. The loss of topsoil is inexorable but it probably takes 30 more years to lose half of it, which of course will cause a population collapse even if everything else were still functioning as well as it is today, which, of course, it wouldn’t be.
2. Desertification is about the same time scale but it seems that it may recover itself at least partially because of natural climate oscillations.
3. Deforestation is about the same 30-year time scale also for catastrophic problems to develop and there are great efforts to try and save the forests which might work and just perhaps in 30 years there will be as many trees as there are now although they will probably be smaller and younger .
4. Poisoning of drinking water can probably be controlled for city water and most people seem to be moving into the cities but uncontrolled water will probably get very bad and local methods will have to be created which really work well.
5. Oceanic pollution will probably continue and the center of the gyres will probably become gigantic cesspools but as it is so very far from what people can personally experience it will be a difficult thing to correct but of itself it shouldn’t cause catastrophe.
6. Shrinking wetlands will impoverish the planet and kill off many species but by itself it will not bring humanity to collapse.
7. Overgrazing will continue and probably reach really bad conditions when population overruns demand the absolute last calorie of food that can be wrung from the soil and grasslands will probably be producing half of what they do today.
8. Loss of wilderness areas will probably not bother people much because they simply will not be used to much wilderness and the transportation needs to access it will seem overly expensive for the rewards.
9. Species loss is a more difficult one to make any decade projections about because species means every other (non-human for this discussion) species, including all of those which interact to keep the planet in ecological balance. Some unanticipated species collapse might have totally devastating consequences.
10. Shortage of firewood will continue to be disastrous for those people who depend upon it for cooking and probably other, possibly solar collectors, will have to be devised to take up the energy for cooking. If that can’t be done those people who depend upon that source of energy will perish.
11. Exhaustion of oil reserves probably won’t be absolute but the price of petroleum will rise and their uses will become more limited and that form of transportation will become more limited. There will then be more emphasis on something similar to what is now considered public transportation.
12. Exhaustion of mineral resources is rather like loss of species because it is impossible to know the things which we take for granted that would without some resource suddenly become very expensive and then unavailable. But our present hi-tech society is probably dependent on literally hundreds of things which nature provides in seeming abundance which could suddenly vanish. Some of these might turn out to irreplaceable but not catastrophic, like the color green on your TV monitor.
13. Siltation in rivers and reservoirs will probably have a major impact on the amount of food which is created because when the dams are silted up there is no storage capacity and thus nothing to water the croplands which are now being watered by those dams. There is a similar problem with silted rivers preventing the smooth flow of bulk goods.
14. Encroaching habitat on arable land has been happening from time immemorial when human populations were smaller but with the now huge population the people themselves are physically occupying the once abundant land with their bodies, homes and highways. This land is reclaimable after a population crash but with great difficulty.
15. Dropping water tables is in the same general category as other mineral resources and as the various aquifers run dry there will be local collapse of food creation and a corresponding decrease of world population.
16. Erosion of the ozone layer is a problem which has been brought under human control, at least during times of relative peace, but if there is real turmoil it may prove of short term benefit to do something which destroys the ozone but this is probably not as big a threat as the other problems.
17. CO2 accumulation is continuing to rise at alarming rates and there isn’t going to be any remedy because it costs so much to sequester CO2 and only half of it could be sequestered even if there was a major effort. Therefore it will continue to accumulate and start becoming disastrous after about 30 years.
18. Global warming is the usual thing worried about with the CO2 level rising but there may be other events like the dying off of high metabolism creatures like hummingbirds followed by the dying off of the whole food chain their pollination supports.
19. Rising sea levels worries a lot of sea front people but of itself shouldn’t cause a problem because people can adjust their behavior in that time scale.
20. Nuclear wastes will probably catch up to us in the form of atomic bombs being created out of uncontrolled waste. The occasional bomb itself will not destroy humanity but the havoc which the terror wreaks and the confusion as to how to cope with these problems may disrupt society so badly that it ceases to function as we know it.
21. Acid rain will probably get worse but as most of that seems to be created in localized power plants and other industrial settings it can probably be controlled to a livable level.
22. Plant disease is a real joker card because a serious disease striking one of the basic foods such as rice, wheat, corn etc. would cause havoc and mass starvation because it would strike suddenly in a period of a few months.
23. Human disease is a instant catastrophe if it is ideally suited to human transmission. For it to be contained would require the instant shutting down of the transportation industry and if that didn’t happen quickly enough the disease would be worldwide in less than a month.
24. Human energy consumption is continuing to expand and humans have an endless need and demand for more energy because it satisfies so many wants. If energy supplies collapsed many people would suffer and because ultimately food is stored energy if that supply was cut off people would starve.
Tomorrow’s blog will be about some interactions among these stressful factors.