Unpredictable extremes of weather could be a huge problem. Simon N. Gosling, a geographer at the University of Nottingham in England, and Robert E. Davis of the University of Virginia agree that hotter weather on average isn't as dangerous as unexpected weather. A study published in the Proceedings of the National Academy of Sciences in April looked at how temperature fluctuations over a single summer affect mortality in vulnerable populations. Researchers found that a few months of rapidly changing conditions—with alternating spells of hotter and cooler weather—tend to produce more deaths, regardless of how hot it is overall. That's especially true in parts of the country that aren't accustomed to such rapid changes. "Variability is really important," Gosling says, "and it has actually been overlooked quite a bit."
Will climate change lead to more unexpected weather? It depends where you are. In Boston, for example, climate models suggest hotter weather over the next few decades while variation stays more or less the same. In Dallas, the average temperature may go up while the variability goes down (which might save lives). It's hard to know for sure what will happen. "I don't think as a community," Davis says, "we understand why the variability changes from place to place."
Have a burning science question you'd like to see answered in our FYI section? Email it to email@example.com.
One can look at past decades of climate change to get an idea of particular trends or not for the future by default*:
Data from Dr. Maue of Florida State University shows global hurricane frequency on average has been actually constant to declining over the past couple decades:
In the case of the subset which is hurricanes with U.S. landfall, data available back to the 1850s (not any exciting trend there either) can be seen at http://www.nhc.noaa.gov/pastdec.shtml
Over the 1950-2000 period, the maximum area of droughts recorded was way back in the 1950s and 1960s in four of six continent-related areas:
There was nil overall average increase in drought area for the world over the half-century period studied.
Sheffield, J., K.M. Andreadis, E.F. Wood, and D.P. Lettenmaier. 2009. Global and Continental Drought in the Second Half of the Twentieth Century: Severity–Area–Duration Analysis and Temporal Variability of Large-Scale Events. Journal of Climate, 22, 1962-1981.
Thus, unsurprisingly, also Kunkel et al. 1999 note "no apparent trend in climatic drought frequency."
Kunkel, K.E., Pielke Jr., R.A. and Changnon, S.A. 1999. Temporal fluctuations in weather and climate extremes that cause economic and human health impacts: A review. Bulletin of the American Meteorological Society 80: 1077-1098.
On hot spells versus cold spells, actually more people die from cold than heat.
The Goklany report notes that from 1979-2006, 19000 people in the U.S. died from excess cold, double the number related to excess heat.
When there are heat spells, little helps more than inexpensive electricity for air conditioning, especially for the elderly.
* With that said, a likely possibility differs from the past few decades; as astrophysicist Dr. Abdussamatov, head of the Russian segment of the International Space Station, explains and discusses, there is reason to suspect potentially onset of "the 19th Little Ice Age in the past 7500 years in 2055 [A.D.] ± 11 [years]":
I hope with the up and coming climate change, the adapt the chocolate bean plants to survive. For humanity to survive the future, we must have chocolate!
I work at the Capitol Tower. Why are we always the ones to get blown up?
HClark's post, and the material presented with uit, isa an eminent example of playing with numbers to arrive at an illegitimate "conclusion". Even whereinformation provided or the interpretation of it are not erroneous or even false, and there are a number of examples of that, the statements arrived at are invalid.
For example, notice Dr. Maue's craven and underhanded choice to start the chart of worldwide hurricanes at 1978. The very shape of the leftmost tail indicates that hurricane numbers had actually been steeply increasing to that point. But Dr. Maue didn't want that information to be imparted! And nbotice HClark's untrue description of hurricane numbers as "constant to declining". The number of major hurricanes is actually increasing, from about 21 per year to 24. And notice how, toward 2012, the difference between the grqaphs is narrowing. That means the difference between all storms and only major storms in diminishing! In other words, the mragin that represents non-major storms is going to 0! Eventually, there will only be major hurricanes, and those will be increasing in number!
And, as for the material on hurricane landfalls ostensibly from NOAA, notice the eminently suspicious fact that it covers 2001 to 2004! That's almost a decade ago and they didn't update it! It looks like they deliberately left out the massive events of 2005 and afterward. But there is something else. Notice that the URL for that page says "noaa.gov/pastdec.shtml". Ostensibly, according to the search engines, that material is from the National Hurricane Center Data Archive. But, if you look at the web page for the archive at NOAA, there is no direct link. There is, however, a link that does provide their claimed record of major hurricanes making landfall between 2001 and 2010! And that information shows 7 such events, in contrast to the 3 mentioned on the web page HClark tries to steer you to, and those 7 all happened after 2004, none before! It looks very much like the web page HClark references is a fraud, placed perhaps illegally on a government web site to promote the anti climate change agenda!
There are no direct links for the claimed .pdf about clobal contienntal drought. The listed URL only takes you to a home page for Washington University. If you try to go by authors or titles, you come up with nothing. This seems as fraudulent a claim as all the rest.
Add to that the wretched dodge that cold kills more than heat. So, if the temperature rises to 700 degrees everywhere, comparable to the surface of Venus, it will still be okay, because more people died from cold exposure than from heat.
To defend a lie means you cannot depend on its inherent legitimacy or validity. As a reuslt, those who promote lies do not tell the truth. They play with facts; misinterpret them; withhold them; send people to links that, at best, would require months of searching to find what they were referring to; they create falsified web pages and link to them. The cravenness of the opponents of climate change is evident in their deceitful machinations.
Sorry, julianpenrod. HClark wins, you lose. HClark posted persuasive points backed with links and data. You...not so much. Although your silly statement about 700 degree temperatures was amusing.
Guess what? If the temperature rises to 700 degrees, which I might point out it won't ever do, you won't have to worry, because you'll be dead already.
Maybe lay off the whole "promote lies" argument and try some facts and logic. Better yet, allow yourself to be persuaded by facts and go look them up yourself.
On hurricane frequency and strength:
Also, the NOAA link HClark posted covers from 1850 to 2004. If you have more recent data, please post it to support your argument.
If global warming is causing an increase in hurricane frequency as you propose, then we're in luck because there has been no appreciable warming for more than a decade as Phil Jones stated:
The link to the Goklany report, published in the Journal of American Physicians and Surgeons, works just fine, and it's very persuasive. Not that we needed to read it to be reminded of what we all knew: cold snaps kill many more people than do heat waves. It also illustrates the point of this article and that is that extreme swings in weather or temperature are deadly.
the craven who attack the truth so often cannot avoid making blundering louts of themselves.
laurenra7 t\kes it upon themselves to dispute everything I said, even if they have to make an imvbecile of themself doing it.
For example, they defend HClark's claim that hurricanes over the last couple of decades have been flat or even decreasing, and, to do it, they point to an article in Science Daily that actually admits that the frequency of hurricanes has been increasing!
And my argument with respect to the "NOAA link" provided by HClark was that it stops at 2004, even though there are at least seven years of information since then! That cannot be considered as current as HClark suggests their references are! laurenra7 challenges me to provide more recent data, as if I was drawing a conclusion based on what was on the web link. But I wasn't. I was complaining about the unjustifiable lack of recent information. laurenra7 is determined to accuse me of making false statements even if they have to pretend I made statements that I didn't make.
Too, I didn't say global warming was causing an increase in hurricane frequency. Another lie. I said that the chart that HCLark themself so proudly provided, if looked at with more than a cursory eye, showed an increasing trend in major hurricanes and a decrease in the number of total hurricanes, which definitively means that minor hurricanes are becoming nonexistent, that only major hurricanes will exist.
laurenra7 makes a fool of themself, too, by describing the link to the Goklany report as working fine, as if I was wrong. I didn't say that link didn't work! I said the supposed link to drought information didn't lead to the report!
In short, laurenra7's method for "disproving" my statements is to credit statements to me that I did not make! laurenra7 is utterly without legitimacy.
Thank you laurenra7.
The graph of global hurricane frequency in my prior comment extends up to 2012.
While http://www.nhc.noaa.gov/pastdec.shtml does not in contrast, such a look at entire decades at a time extending back to the mid-19th century is more about the long term picture.
The latter shows, for full decades, the number of major hurricanes (category 3 or more) striking the U.S. to be:
1851-1860 = 6
1861-1870 = 1
1871-1880 = 7
1881-1890 = 5
1891-1900 = 8
1901-1910 = 4
1911-1920 = 7
1921-1930 = 5
1931-1940 = 8
1941-1950 = 10
1951-1960 = 8
1961-1970 = 6
1971-1980 = 4
1981-1990 = 5
1991-2000 = 5
Another NOAA publication updates to 2007 at http://www.aoml.noaa.gov/hrd/hurdat/ushurrlist18512007.txt
While such fluctuates up and down, the main observation from the above is how there is not a skyrocketing increase. There were 34 during the half century from 1901 to 1950 versus 28 during the next half century from 1951 to 2000. Nobody can predict exactly what the number will amount to over another half century like 2001-2050 for the rest of our natural lifetimes, but a look at the past helps, and personally I'm not too terrified of hurricane number increase, to say the least.
Naturally there is no perfect global hurricane data extending back to 1850, as too many hurricanes were missed before the modern era of global electronic news coverage (and hype), like a scientist in the U.K. in the 19th century would not necessarily ever know of every hurricane occurring in the more remote regions of the oceans. (And many people today are limited in awareness of what happened in the past like the Galveston hurricane of 1900 which killed 8000 people in Texas). But global frequency when seen and a longer dataset when available are a good combination.
The prior link to Sheffield et al. 2009 on drought is not working now, probably a result of me being careless in not double-checking when using links anew in a collection where some are months old, but that is trivial to fix, as it is also online here:
Like they say, over the latter half of the 20th century, "globally, the mid-1950s showed the highest drought activity and the mid-1970s to mid-1980s the lowest activity."
While counterintuitive to many people, the cold last glacial maximum 18000 years ago was actually when the rate per year of precipitation falling over land was lowest compared to since then (colder temperatures meaning less evaporated from the oceans), and, accordingly, such had the greatest desert extent by far, including polar deserts which are cold but have nil precipitation, as illustrated in http://www.esd.ornl.gov/projects/qen/lastgla.gif which is from an U.S. government Oak Ridge National Laboratory study at http://www.esd.ornl.gov/projects/qen/nerc.html
Conversely, when this mostly water-covered object (Earth) was warmed overall, since not just local land warming but warming of the oceans too occurred, more water entered the water cycle to fall over land, reducing desert extent. They remark:
"By 8,000 14C y.a., the Earth was under a full interglacial climate, with conditions warmer and moister than present in many parts of the world. Tropical forest in Africa (and probably also Asia) was expanded in area, and the areas of desert in Africa and Asia were much reduced."
The time 8000 years ago was the Holocene Climate Optimum, as seen in http://tinyurl.com/3d4mrbt which is a plot of the past 200-11000 years presenting in graphical form part of the less convenient text table data at
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/greenland/summit/gisp2/isotopes/gisp2_temp_accum_alley2000.txt (tinyurl backup if long link gets broken: http://tinyurl.com/yzzatz4 )
Back to the ORNL study, in potential vegetation, the charts illustrate:
Much colder than now:
Warmer than now:
While not a particularly meaningful number, since really it depends on the choice of start and end dates (much like the different trend examples in http://earthobservatory.nasa.gov/Features/ArcticIce/Images/arctic_temp_trends_rt.gif on another topic), there was around a 2% increase in precipitation over 1901-2008, nil increase in overall drought.
I am seriously thinking about moving back to a cooler climate, Venus. I came here to help Terraform earth for the Venusians. Earthling don't need my help here there doing a better job than we can, thanks earthlings...
While the surface under 90 times the mass of Earth's atmosphere and sulfuric acid clouds is a vastly different matter, ironically Venus is actually relatively benign at the point in its upper atmosphere corresponding to 1 bar of pressure (under a mass of atmosphere which would be like sea level on Earth):
To quote from http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20030022668_2003025525.pdf :
“Viewed in a different way, the problem with Venus is merely that the ground level is too far below the one atmosphere level. At cloud-top level, Venus is the paradise planet. As shown in figure 2, at an altitude slightly above fifty km above the surface, the atmospheric pressure is equal to the Earth surface atmospheric pressure of 1 Bar. At this level, the environment of Venus is benign. Above the clouds, there is abundant solar energy. Temperature is in the habitable “liquid water” range of 0-50 [degrees Celsius].”
In the context of how Venus is hit and warmed by double the watts per square meter of incoming solar radiation (orbiting closer to the sun than Earth), that is pretty notable in context.
In fact, some have proposed colonizing the Venus upper atmosphere in giant floating (blimp) cities someday, as in the prior NASA paper link. Unfortunately with an atmosphere massing 500,000,000 billion tons (4.8E20 kg), astronomical compared to human industry, we couldn't change its mass much in a million years short of godtech, so the surface is out short of Singularity-like scenarios. Personally I doubt floating residences would be overall attractive or practical compared to O'Neill habitats in space, though (e.g. http://settlement.arc.nasa.gov/75SummerStudy/Design.html + http://en.wikipedia.org/wiki/StarTram + http://neofuel.com/index_neofuel.html ), and even Mars is less dangerous in the sense of not having to worry about accidental loss of buoyancy leading to crashing down below.
I proposed tarraforming Venus years ago by placing an asteroid at the L1 location in front of Venus by re-route an asteroid, yea it will take a lot of energy and effort, and place in the L1 position and blow half of it up leaving the core. The resulting mass would orbit the core at the L1 location. There would be a large percent of shade in front of Venus enough to cool it down a bit, I still think it would work. I guess I got to use to earth weather.
In microgravity, perhaps even magnetic fields extremely weak and thus by a number of orders of magnitude huge relative to the size of relatively small superconducting electromagnets might be used to guide and control, if helpful, vast clouds of dust. That could be if making ferromagnetic dust by pulverizing an asteroid with nickel-iron content. I don't have calculations for requirements there versus limiting drift over time from solar radiation pressure on dust (varying a bit between grains of dust not fully identical to each other) and don't think anything short of a massive space civilization already developed first would be likely to carry out endeavors on that scale, but, if there was such eventually, who knows.
But, with that said, the magnetic field idea may be fancier than needed in that particular application; I was borrowing it from another scenario. Indeed, as you imply, even the weak gravity of an asteroid for getting clouds of dust slowly orbiting it might be enough, with no need for a magnetic field there and no need for ferromagnetic dust. In fact, the "solar sail" effect of solar radiation pressure may not be a problem after all, as I was momentarily forgetting how, in that particular case, it would be providing micro delta v on one side of the orbit in the opposite direction to when on the other side, thus mainly neutralizing itself in net effect, not too building up over time. Meh, now is too late at night for me to still be awake.
Really, I'd need to get into quantitative data and calculations for how large of an asteroid would be needed to produce enough (weak) gravity to allow an orbiting dust cloud of great enough radius for significant shading effect, for dust lasting in such a microgravity orbit versus micro perturbations over time even down to the tiny tidal effect of distant Jupiter. But it is an interesting thought in any case.
julianpenrod, I wasn't accusing you of making false statements. I was pointing out where you are wrong. There's a difference.
If you peruse the NOAA website you'll find hurricane and tropical storm (cyclone) totals all the way through 2011.
You can count the most recent ones yourself and do a 5-year average to pick out trends. You'll see that through the 1990's the frequency of cyclones increases ever-so-slightly, but as it heads into the 21st century, they decrease slightly too, even accounting for the extreme year of 2005 with an unusually high 28 cyclones. In 2010 and 2011 they increase slightly again.
Note the comment at the bottom of the ScienceDaily news article. The study was done by scientists who believe a change (warming) IS happening, but they also caution against drawing any meaningful conclusions from the study:
"because these types of storms are so uncommon, it will take many more years of data to reliably assess this issue."
This could be applied to determining human contributions to climate change as well. A lot more data needs to be accumulated to establish whether or not humans are causing significant warming of the atmosphere and ocean.
Meanwhile, don't worry. Be happy.
H Clark, all the dust being in the L1 position it may not need much of a core to keep the dust there once it settles. A Satellite placed in L1 position may be a good place to extrapolate out how much of it maintain its position at a L1 location, just a little movement of dust may be a problem.
With that being said I also proposed on Space.com board many times over the past 12 years of placing a magnetically strong earthlike magnetic field at the L1 position controlled by a large diameter thin wire ring that would control the magnetized dust particles. The solar wind would have an effect on it so a solar cell ion propulsion sytem would be needed to keep the ring in place.
Climate is Geography,Ecology is life in a area,Enviroment is the sum of weather interactions and happenings in a area over time...weather is the result of tempature+humidity+evaporation/percipitation
Weather Variability gets really extreme..expecially during amplified El Ninos and La Ninas like we been having from the added heat being vented from accelerated plate tectonics also causing more and more earthquakes and subduction volcanos like Iceland to re-awaken
Whether or not this finally clicks average global tempature from 15c,where its been for 10,000 years,to 16c remains to be seen as these localized "spurts" causing localized "Warming" happen all the time as does regional plate activity going down causing regional "Ice Ages" but AGT still stays 15c
Great explanation. It's just a pain. Happens every time we rebuild the damn thing.
As illustrated by the international database of the U.S. census at http://www.census.gov/population/international/data/idb/images/worldgr.png , world population growth rate was 2.2% in the early 1960s, then has basically continuously declined, to about 1.7% in 1979, 1.3% in 2000, 1.1% in 2011, and so on. As the prior graph illustrates, they estimate it to drop to 0.5% by 2050 and then below.
Such is influenced by what is called the demographic transition. The fertility rate is the average number of children born per woman statistically in a lifetime, where, since women are half the population, below 2 in a country means it is headed for long-term population decline in the future (short of immigrants entering and often even when many do depending on the relative numbers), while continuation of population growth for long would require above 2.
With a lag time, fertility rates decline after a country modernizes. For instance, while the countries comprising the European Union once had a fertility rate far above 2 per woman and above replacement level, by 2010 such dropped to 1.58 as shown at https://www.cia.gov/library/publications/the-world-factbook/geos/ee.html . As another example, Japan has a fertility rate of 1.39 now, and, though there is a lag time in general, they are one of the countries which has begun population decline. The U.S. Census, for international projections, estimates that world population is projected to peak at around 9-10 billion, around later this century. And, for example, http://www.nature.com/nature/journal/v412/n6846/abs/412543a0.html estimates "there is around an 85 per cent chance that the world's population will stop growing before the end of the century" and "a 60 per cent probability that the world's population will not exceed 10 billion people before 2100." China's population is estimated to peak at 1.4 billion in around 2026, which is 14 years from now, as http://www.census.gov/newsroom/releases/archives/international_population/cb09-191.html notes, with that for India occurring later but India's fertility rate declining over time.
Speaking of the long term, human civilization's average electrical generation of around 2 terawatts plus several TW other energy usage compares to 200000 terawatts of sunlight hitting Earth (while energy at the rate of 400,000,000,000,000 terawatts is wasted by the sun dissipating into deep space).
Applied technology helps. For example, average U.S. corn yields quadrupled over the past 60 years in bushels per acre, and biotech test plots are already getting another doubling beyond the current average: http://www.aleph.se/andart/archives/images/Biodesic_US_corn_yield-thumb.png
In bulk, corn now actually costs just $300 per ton, like $0.08 for a half pound, even though such seems alien to someone experiencing how small cans of corn at the grocery store cost $0.50+ each retail due to added costs from processing, packaging, distribution, middlemen, and profits.
That is the result of mechanized agriculture and biotech. (Production of nitrogen fertilizer only utilizes about 5% of global natural gas production, while able to be produced from nitrogen in the atmosphere, hydrogen from any source whether natural gas or water, and energy from any source for the Haber process).
The mass of radioisotopes in human nuclear waste contrasts to those naturally in the crust: "Since the fraction of a radioisotope's atoms decaying per unit of time is inversely proportional to its half-life, the relative radioactivity of a quantity of buried human radioactive waste would diminish over time compared to natural radioisotopes (such as the decay chains of 120 trillion tons of thorium and 40 trillion tons of uranium which are at relatively trace concentrations of parts per million each over the crust's 30,000,000,000,000,000,000 ton mass). For instance, over a timeframe of thousands of years, after the most active short half-life radioisotopes decayed, burying U.S. nuclear waste would increase the radioactivity in the top 2000 feet of rock and soil in the United States (10 million km2) by ≈ 1 part in 10 million over the cumulative amount of natural radioisotopes in such a volume [ http://www.phyast.pitt.edu/~blc/Perspectives_on_HLW.htm ]."
Didn't notice basic facts for any real understanding whatsoever, like the above, ever honestly revealed by the ideologues prophesying how terrible it is? Unfortunately, like there are mass protests against nuclear waste disposal but never mass protests in favor of nuclear power, there is a slant in too many of those selling memes. The same kind of ideological movement is what leads to the recent claim that [California will] "lose one foot of land in 10 years" [in sea level rise] and the claim about temperature rise of 7.2 degrees 2012->2060 (around 1 degree / 7 years on average). I'm saving the articles reporting those at http://www.popsci.com/science/article/2012-06/study-says-california-sea-levels-will-rise-more-five-feet-century and http://www.popsci.com/science/article/2012-06/climate-change-here-its-time-get-ready , since, as discussed in my comment at the former on how it is demonstratively invalid, such will be excellent demonstrations a few years from now.
There is a superficial edifice aimed at looking impressive, surrounding a rotten core. A classic example is the widely reported 97.4% consensus figure, often with no source mentioned but from Doran & Zimmerman 2009. One minor, little problem: Unlike almost all of the target audience, I actually read the study (at http://tigger.uic.edu/~pdoran/012009_Doran_final.pdf ). It based its figure on two survey questions in an online poll: (a) whether temperatures rose since the pre-1800s level, and (b) whether humans have a significant effect on temperature change. One answers yes to both as the pre-1800s were the Little Ice Age, and a significant effect in science means non-zero, as in anything down to what color houses are painted (albedo) having an effect. But neither is the matter here. How such is reported speaks volumes about the trustworthiness of those doing the reporting but not so much about actual consensus on predictions to those beyond mathematically illiterate binary thought.
As for the future of global temperatures, the first matter to understand is the past, not the version of hype but the actual picture, as seen, for instance, in the following three graphs, which can be looked at closely for how recent temperature change actually compares to the past:
#2 is from an European study for the past 2000 years at http://www.uni-mainz.de/eng/15491.php
#3 is a chart of GISP 2 reconstructed temperature over the past 200-11000 years versus CO2, different from ice age graphs more commonly publicized because it is not so zoomed out to million-year scale, so the lag time of centuries for oceans thousands of meters deep to warm to their depths (for warming to cause CO2 increase afterwards) is not a mere pixel or overlapping line.
For #3, data is from:
Incidentally, if anyone really wants to learn, after looking closely at the above graphs and their implications, read, among much else:
(emissions increased by an order of magnitude over that period)
Failing that, though, look back 5 or 10 years from now. Such as the 1 foot California sea level rise in 10 years claim is educational in a way, good for teaching critical thought, as that gets very blatantly tested versus reality; anyone who lives by the beach can see what actually happens.
Aside from all previously discussed, in 1989 the world had an average fertility rate of 3.5 per woman* whereas that decreased by 30% with now the world having an average fertility rate of 2.47 per woman** (about 1.2 descendants per 1 person currently alive, women being about half of the population --- except actually females less than half of children now in the world's largest-population countries of China and India but that another topic).
Replacement level is about 2 per woman, although, more precisely, considering some mortality before reaching reproductive age, the standard figure is around 2.1+ per woman. Once the current world fertility rate of 2.47 per woman decreases further by around 15% (not a matter of halving but of around 15% less), while population growth will continue for a limited time afterwards due to the lag time in age distribution reflecting the consequences of the new fertility rate (what is called "population momentum" or the "population-lag effect"), subsequently then population peaks.
Whereas the world had a population growth rate of 1.3% in 1999, it had a growth rate of 1.096% in 2011 which will soon drop below 1% and so on like the IDB chart linked in my prior comment. 8 billion people will be reached less than a couple decades from now but slower than the last billion people added, then the next billion after that taking much longer, and so on, as in the IDB projection of a peak of <=~ 10 billion people later in this century and as in http://www.nature.com/nature/journal/v412/n6846/abs/412543a0.html
However, the capability to learn is dependent on the reader and appears not applicable here with you already skipping over the more extensive discussion and references in my prior post. I wonder if you even believe Japan (1.39 fertility rate per woman and 0.7 per person) has the same number of children getting born per couple now as in the early 20th century rather than having already entered population decline, believe Germany has the same age distribution as decades ago (rather than, for instance, even between the year 2000 and now a drop from 16% of the German population being children age 0-14 to such being 13.3% with median age already reaching 44.9 years), etc.
Nice debate! Let's see if I can add to the discussion. All comments regarding the sustainability of the human population are valid and well established. However, there is one contributing factor not mentioned. In my limited opinion - the discussion must include a key process responsiblefor the development of intelligent life.. Natural Selection or survival of the fittest.
Although HClark's intimate knowledge of the cosmos and the Venusian atmoaphere is quite impressive - we cannot forget that Natural selection is a process perfected - not by scientists - but life.
There is a reason why (intended or not) cancer and other deadly diseases - including human hostility is on the increase. Like wild animals - when the competition for natural resources become greater - survival (natural selection) more likely than not will favor the strongest or better equipped.
Global warming, unsustainable growrh, birthrate decline, and starvation are all signs that natural selection is indeed in progress.