@ R. Dow Good grief. The observed trends conform every closely to the predictions in the years for which there is data. What makes you think extending the observed trend lines without any data to base them on is valid? The predictions are not linear for very good reason. So why should you expect the reality to be linear? It never has been except for short segments like the one to which you refer. Learn how to interpret data before making silly, extremely naive remarks like this. A big whole in the knowledge of science, empirical data collection, and interpretation is behind this comment. No remotely competent scientist, mathematician, or even engineer would make a comment like this. Maybe, just maybe, a lousy cookbook engineer without a creative bone in his/her body or any understanding of basic underlying principle could conceivably be guilty of such a comment.

What is the Y axis on this graph? How can non-renewable resources, industrial output, pollution, services and food, be measured and plotted in the same units?

All of these predictions are based on models. First of all, the most important things in a model are those it doesn't contain. Second, future cannot be predicted because the future is always under construction. Last but not least, analyses of this sort should take into account one of the salient characteristics of our times - complexity (which can be measured and which can only grow to certain thresholds). The limits to growth (of any system) are dictated by the so-called critical complexity (think of it as the highest value of cholesterol that gets you to a pre-cardiac infarction state). Once you get close to critical complexity your system becomes very fragile and has the capacity to suddenly deliver unexpected behavior (this is called spontaneous mode-switching or phase-changes). According to our analyses, based on data from the World Bank, the World, as a system, will reach critical complexity around 2045-2050 (if the current rate of complexity increase continues,..... an assumption which remains to be monitored).

Dear editors, Pure Bunk! I am just now getting through the April issue, and was amazed to see the article by a senior editor Mark Strauss, about the negative predictions for the future (based on the book The Limits of Growth ). Most readers weren't as fortunate as I've been, and didn't study economics in university ( in the 1990's as part of a Business Administration degree).Therefore, they have no way of knowing that the once-accepted Malthusian theory predicting the world would run out of food due to man's inability to meet population-growth needs, has been proven entirely wrong! Furthermore, around 1990 an economist from MD. University placed a $1000 bet against a biologist from another American university. He stated that contrary to many biologists' views, based on economics theories and the past, all major commodities (including wheat,) would go down considerably during the following ten years. Needless to say the economist won the bet! Most commodities indeed went down by large percentages, some by smaller amounts, yet they were all cheaper. (I saw that show right here in Israel, twice, on one of the cable channels.) I also checked the article on your Web-site and immediately saw the three false assumptions the writers had made. They didn't take into account A) price mechanisms, B) advancements in technology, C) they treated the world as a whole. These crucial points are enough to invalidate the whole "prediction." In addition, nowhere in your report do you mention what fields the professors who wrote the report have their degrees in. Was any of them an economist? That seems highly unlikely considering the above omissions. One really wonders why a senior editor such as Mark Strauss didn't do his homework? The article will no-doubt worry many readers, to say the least. To sum it up: not everything presented at the Smithsonian Institution is sacred. Sincerely yours, Joseph B. Israel

The economic collapse is normally, I think, the most problems of the world is, how if women will be collapsed of environmental problems (human made) of economy growth. God Bless You from Indonesia. Bakti Social Borunauli Foundation of Indonesia.

I have been researching the global-resources problem for roughly the past ten years. My latest "essay" on it is titled DEPLETION OF NATURAL RESOURCES WILL CAUSE THE DECLINE OF MANKIND. It is online at www.decline-mysite.net Until today I was not aware of the 1972 MIT study. Although their efforts were forty years earlier,I am pleased with how similar our conclusions are. For instance: please note how comparable my curves (about two thirds through the essay) are with those developed by MIT, yet they and I had no contact with each other. The world has seen a great many ecological, weather, resource depletion, and economic developments since 1970 (all of them bad news) therefore those of us concerned with it can see the decline of humanity even more clearly than that early team was able to. Striving to make it broadly inclusive and easy to read, this essay was written for a more general audience than their work was. Francis Reynolds

Even a cursory examination of the graph shows that if you extend the "Observed Trend" lines they are nowhere near the "Trend Predicted" lines. So how does that support the "Limits of Growth" projections?

"The environmental movement has always been about seizing power by making up one phony emergency after another." Yeah that's really worked for them, hasn't it? Since the grand-wizards of the environmental (surely pseudosciences at best) sciences seized power with all those fake emergencies and brainwashed the planet with polar bear cub images everything's gone to hell. It's a miracle that the fossil-fuel industry has survived. The comment is especially ironic considering that the emergencies mentioned are intimately tied, still present and that investigating their relationships to one-another was part of the reason for the research in the first place. In any event, the experiment is running but it's little comfort to those who are persuaded by the quality science behind this research, that those who aren't will have to share in whatever the consequences of inaction will be. What IS a comfort, however, is that having got a bloody nose with CIV 1, some lessons will be carried into CIV 2.0, who won't, in any event, have the sort of resources to throw about waantonly like their forebears.

Jorgen Randers discusses the misinterpretation of economic growth which has led several contributors to deny that Limits to Growth spoke of the possibility of continued growth. Limits to Growth only dealt with limitations deriving from physical factors. The authors did state that it might be possible to have an increase in value (economic growth) that does not entail an increase in resource consumption or waste production. They are correct in stating this as economic growth is not fundamentally linked to either resource consumption or waste production. The fact that economic growth has, historically, always been associated with resource consumption and waste production does not change this fact.

The environmental movement has always been about seizing power by making up one phony emergency after another. The population crisis was one, then the energy crisis, and now global warming/climate change. Julian Simon's "The Ultimate Resource" proves that population growth is actually beneficial. Why would they lie like that?

Short of a nano material PV / thermoelectrical / ultracapas­itating Black swan, What we can do now with "off the shelf" technology­, what I proposed at the Commission for Environmen­tal Cooperatio­n. The most cited soil scientist in the world, Dr. Rattan Lal at OSU, was impressed by this talk given to the EPA chiefs of North America, commending me on conceptual­izing & articulati­ng the concept. Bellow the opening text. A full Report on my talk at CEC, and complete text & links are here: http://tec­h.groups.y­ahoo.com/g­roup/bioch­ar-policy/­message/32­33 The Establishm­ent of Soil Carbon as the Universal Measure of Sustainabi­lity The Paleoclima­te Record shows agricultur­al-geo-eng­ineering is responsibl­e for 2/3rds of our excess greenhouse gases. The unintended consequenc­e; flowering of our civilizati­on. Our science has now realized these consequenc­es, developing a more encompassi­ng wisdom. Wise land management­, afforestat­ion and the thermal conversion of biomass can build back our soil carbon. Pyrolysis, Gasificati­on and Hydro-Ther­mal Carbonizat­ion are known biofuel technologi­es, What is new are the concomitan­t benefits of biochars for Soil Carbon Sequestrat­ion; building soil biodiversi­ty & nitrogen efficiency­, as a feed supplement cutting the carbon foot print of livestock & in situ remediatio­n of toxic agents, Modern systems are closed-loo­p with no significan­t emissions. The general LCA is: every 1 ton of biomass yields 1/3 ton Biochar equal to 1 ton CO2e, plus biofuels equal to 1MWh exported electricit­y, so each energy cycle is 1/3 carbon negative Beyond Rectifying the Carbon Cycle, the same healing function for the Nitrogen and Phosphorou­s Cycles Since we have filled the air, filling the seas to full, soil is the only beneficial place left. Carbon to the Soil, the only ubiquitous and economic place to put it.

A lot of sophistry and willful denial in the posts above. Basically, a lot of countries are ramped up for massive overpopulation set to vastly exceed carrying capacity. If they all want to have 10 children who, in turn, all want 10 children then the result is obvious. And on that day the fight for resources turns ugly. 2030 dudes. The number is in.

People interested in this discussion might be interested in reading my book (in French) « Thermodynamique de l’évolution ». The evolution of mankind is a dissipative process. As such it is subject to self-organised criticality. The collapse of a society is a consequence of this process. Societies self-organise to dissipate energy. The more energy they dissipate, the more their environment evolve, the more they have to reoganise themselves. It leads to what biologists call « the red queen effect ». One has to run as fast as possible to stay in place. At some point species become extinct and/or societies collapse. This is what we are now experiencing.

Some silly comments up above. The human brain is useless without food, and food requires energy to be produced. In fact, nothing whatever happens without energy, and that includes the 'hydrogen economy' (unfortunately, hydrogen is a vector, not a source). And the C of R didn't set out to be catastrophic, indeed they doubted their initial findings. Then - like Bartlett with Hubbert http://www.hubbertpeak.com/bartlett/hubbert.htm They ran it with 'double resources' (two planets, in other words)and found almost no change to the outcome.