Wednesday, December 26, 2007

Iranian Navy receives stealth-capable submarine - national TV

Iranian Navy receives stealth-capable submarine - national TV

28/ 11/ 2007

TEHRAN, November 28 (RIA Novosti) - Iran's Navy commissioned Wednesday a domestically designed and produced light submarine featuring extended stealth capability and strong firepower, state television reported.
The submarine, dubbed Ghadir, is reportedly fitted with noise-reduction features and is capable of firing missiles and torpedoes simultaneously.
"This submarine is equipped with advanced weapons and electronics systems. It has been developed in the last decade by [Iranian] scientists and engineers," a TV program quoted Navy commander, Admiral Habib Sayyari, as saying.
The admiral also said the Navy commissioned a destroyer and a missile boat.
According to various intelligence reports, Iran has been spending a considerable share of its defense budget on modernizing its naval forces over the last decade.
"The Iranian Navy - surface ships, submarines and naval bases - is equipped with all the necessary modern weaponry, including missiles," Sayyari said. "Their [the missiles] range is sufficient to protect effectively our southern flank in the Persian Gulf."
In a separate development, Iran, which received no invitation to the Mideast peace conference in Annapolis, announced on Tuesday that it had produced a ballistic missile with a range of 2,000 kilometers (1,240 miles). The missile's range would allow it to reach Israel, as well as United States military bases in the Middle East.

Russia to sell advanced air defense systems to Iran - 2

Russia to sell advanced air defense systems to Iran - 2

26/ 12/ 2007

(Adds Russian official's quote, details on Tor-M1 crew training in paras 13-14)
TEHRAN, December 26 (RIA Novosti) - Iran signed a contract with Russia on Tuesday for the delivery of advanced S-300 air defense missile systems to the Islamic Republic, an Iranian news agency reported on Wednesday.
An advanced version of the S-300 missile system, called S-300PMU1 (SA-20 Gargoyle), has a range of over 150 kilometers (about 100 miles) and can intercept ballistic missiles and aircraft at low and high altitudes, making this system an effective tool for warding off possible air strikes on Iran.
"S-300 air defense systems will be delivered to Iran under an earlier contract signed with Russia," the Fars news agency quoted Iranian Defense Minister Mostafa Mohammad Najjar as saying.
The minister provided no contract details or a schedule for future deliveries, Fars said.
The signing of the deal follows last week's session of the Russian-Iranian commission on military-technical cooperation in Tehran, where the sides reviewed existing agreements and discussed future steps to extend cooperation in the military sphere.
The closest western equivalent of the S-300 is the U.S. MIM-104 Patriot system or the U.S. Navy RIM-66 Standard Missile 2 (SM-2).
U.S. authorities have repeatedly called on Russia to stop arms deliveries to countries whose political regimes Washington disapproves of, including Iran.
However, Russian President Vladimir Putin said in October that Russia would not take into consideration attempts to impose arms deal restrictions "based on unilateral and politicized assessments".
He also said deliveries of Russian weapons were aimed exclusively at increasing the defense capability of the countries receiving them, and at maintaining their stability.
Russia earlier supplied Iran with 29 Tor-M1 air defense systems under a $700-million contract signed in late 2005.
In February, Tehran successfully tested Tor-M1s during a military exercise by the Islamic Revolutionary Guards Corps in southern Iran.
The Iranian defense minister said on Wednesday that during last week's meeting Russian and Iranian officials discussed the possibility of using Russian experts to train the crews of Iranian Tor-M1 systems in the Islamic Republic.
Meanwhile, a senior Russian military official said that dozens of Iranian Tor-M1 specialists, including radar operators and crew commanders had already completed training in Russia in 2006 and 2007.
"They [the Iranians] have successfully completed the training program and returned home," said Colonel General Nikolai Frolov, commander of the Ground Forces' air defense.

Tuesday, December 4, 2007

XDR-TB is taking its toll on patients

XDR-TB is taking its toll on patients
14 November 2007, 09:23
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By Louise FlanaganSouth Africa has identified 481 extremely drug-resistant tuberculosis patients so far - and nearly half have died.Statistics from the Department of Health show that 216 XDR-TB patients died by the end of last month, while almost 90 percent of the survivors - 235 - were in hospital. The department recorded just five patients who defaulted on treatment and three more who had not started treatment.Gauteng has seen 37 patients, or 8 percent of the total. Of these, 11 have died and 20 are being treated in hospitals.The biggest caseload is in KwaZulu Natal, the province where the disease was first identified in early 2005. It has seen 188 cases, or 39 percent of the country's total.The Eastern Cape has the second-highest burden, with 157 patients (33 percent), followed by the Western Cape with 64 (13 percent) and then Gauteng.The department said the statistics reflected only true XDR-TB cases.XDR-TB is TB which is resistant to the two first-line drugs used against TB plus at least two of the six main classes of second-line drugs.The Health Ministry emphasised yesterday that all confirmed XDR-TB patients would be admitted to multi-drug-resistant TB units until they tested negative, which usually took at least six months.
This article was originally published on page 2 of The Star on November 14, 2007

Why quarantine may backfire

Why quarantine may backfire
Created: Wednesday, November 14, 2007
Recently a patient was shot and a guard stabbed when XDR-TB patients were protesting at the Sizwe hospital in Edenvale. According to reports the patients were unhappy with some of the medicines they were receiving and wanted passes allowing them to leave the hospital.

AdvertisementThe incident illustrates some of the difficulties regarding enforced isolation of XDR-TB patients and is symbolic of what some critics consider to be the department of health's harsh response to the threat posed by XDR-TB.In fact, at some sessions at last week's 38th Union World Conference on Lung Health the general feeling seemed to be that forced isolation is not the most effective way to face the threat of XDR-TB.
According to Nathan Geffen, spokesperson for the Treatment Action Campaign,incarceration is a bad idea for various reasons, which he lists as follows:
It is at hospitals and clinics that most XDR infections are taking place.
It can never be done on a scale that would make a significant difference to the epidemic.
It scares people off getting screened for TB and therefore might have a very deleterious effect on managing the epidemic.
People who get locked up without having committed a crime realise their human rights are being breached. Sometimes they riot, as happened at Sizwe hospital. It's particularly cruel to incarcerate people with fatal diseases for six months or more, especially children.
In a statement on the issue, the South African Medical Research Council warns that, "Public anxiety coupled with the risk that XDR-TB may rise to epidemic levels in SA is putting increased pressure on government and public health authorities for quarantine of patients and coercive measures to curtail the spread of XDR-TB. The dual stigma associated with TB and HIV, now compounded by XDR-TB, poses a real risk of driving the XDR-TB problem underground, especially if isolation measures are coercive. This is a situation that SA can ill afford."
Perspective on the diseaseAccording to Judy Seidman, writing in the Mail and Guardian, quarantine of actively infectious people forms a standard part of the medical response to drug-resistant TB. The emphasis here is very strongly on "actively infectious."
She points out that, "many people with TB (and even XDR-TB) are not infectious. Patients who do not cough do not spread infection through the air. Patients who respond to treatment are no longer infectious after the drugs take effect. Patients need to be quarantined only until the drugs start to work - for days, not weeks or months."
On a similar note, much of the societal concern with drug-resistant forms of TB seems to be based on misconceptions regarding the disease.
According to the World Health Organization (WHO), drug-resistant forms of TB are not more infectious than strains that are not drug resistant. In fact since they are less prevalent, the risk of being infected is much lower.
According to the WHO, "the majority of healthy people with normal immunity may never become ill with TB, unless they are heavily exposed to infectious cases who are not treated or who have been on treatment for less than about one week. Even then, 90% of people infected with TB bacteria never develop TB disease. This applies to XDR-TB as well as to ‘ordinary’ TB."
Why HIV ups the riskThus, unless your immunity is compromised and you are in relatively close contact with an infected person in a closed space, the risk of infection is very low. This is why there is a particularly high risk of drug-resistant forms of TB spreading in hospitals. The compromised immunity is also what places HIV-infected people at a higher risk.
The WHO writes that, "People with HIV infection, however, in close contact with a TB patient, are more likely to catch TB and fall ill. The TB patients whom they meet should be encouraged to follow good cough hygiene, for example, covering their mouths with a handkerchief when they cough, or even, in the early stages of treatment, using a surgical mask, especially in closed environments with poor ventilation."
The way forwardVoices at the conference generally seemed to be in favour of a decentralised, community-based model in the fight against drug-resistant TB.
According to Geffen, "What we've got to do is improve infection control in health facilities."
"XDR patients should be educated on infection control measures (e.g. cough etiquette, maybe wearing masks and a few other simple measures) that can reduce the risk of them passing on the disease," he said.
Government not budgingThe department of health, however, seems very much to be keeping the focus on the isolation of infected persons.
Presenting South Africa's new plan to fight TB at last week's conference, the director general of the department of health, Thami Mseleku, said the department is looking for ways to make it easier to commit people with drug-resistant tuberculosis to treatment facilities against their will.
Until now, health authorities had to get a high court order every time they wanted to commit someone who posed a danger to the community.
"We're still exploring the alternatives," he said. The department was looking for clauses in existing legislation that would allow "a general approach to the matter".
On the legality of enforced isolation, the MRC writes that, "current health legislation in SA empowers authorities to detain patients with infectious diseases until the disease no longer poses a public health threat, thereby allowing quarantine restrictions to be enforced for a limited period. Herein lies the dilemma: many XDR-TB patients may have untreatable disease and confinement would have to be until death or, conceivably, could be indefinite. From a human rights perspective prolonged isolation could, without sufficient procedural safeguards, violate several SA Constitutional rights and international human rights law."
According to Seidman, the media's response, like that of the government, has been rather one-dimensional. She writes, " These articles present arguments saying we should protect ourselves by harsh “control” of sick people, even where this negates their human -- and constitutionally guaranteed -- rights. This theme has become our most common response to XDR-TB."
False sense of securityIn the New England Journal of Medicine, researchers write that, "excessive reliance on compulsory measures can lull the public into a false sense of security and at the same time prompt people who are at risk to do exactly what Speaker did — run." (Andrew Speaker is an American man who fled from authorities after being diagnosed with drug-resistant TB.)
They continue writing that, "fortunately, most persons infected with tuberculosis want treatment and have no desire to infect others. When clinicians and health officials work with patients and have their trust, most will co-operate. By ensuring that coercion is used only when less restrictive alternatives will not work and with due regard for the rights of those detained, the law can foster public trust, minimizing the need for compulsion and laying the groundwork for the comprehensive and costly control programs needed to prevent the spread of XDR tuberculosis and other contagious pathogens."
- (Marcus Low, Health24)

SOUTHERN AFRICA: Struggling with soaring cereal prices

SOUTHERN AFRICA: Struggling with soaring cereal prices
Photo: IRIN
Bread is not on the menuJOHANNESBURG, 12 October 2007 (IRIN) - Record high wheat prices globally are forcing consumers in Southern Africa to dig deeper into their pockets: the price of bread has almost doubled since the beginning of the year, and according to the UN's Food and Agriculture Organisation (FAO), have already caused food riots in some parts of the world.Wheat and maize prices have been at their highest in the past few months: the price of yellow maize doubled from an average of US$88 per metric tonne (mt) in 2000 to $177 per mt in February 2007, while the price of wheat rose from an average of $119 per mt in 2000 to $277 per mt in August 2007. The combination of higher export prices and soaring freight rates has pushed up domestic prices of bread and other basic foodstuffs in importing developing countries, hitting the group of Low-Income Food-Deficit countries particularly hard, said Paul Racionzer, of the FAO's Global Information and Early Warning System. A drop in production has been reported in major exporting countries – which are also among the leading stockholders – notably the United States, where stocks are forecast to sink to a 10-year low of 11 million mt, as well as in Australia, Canada and the European Union (EU), said the FAO's Crop Prospects and Food Situation report for October. "Among other countries, sharply smaller stocks are forecast for Egypt, Morocco, Tunisia, Turkey, and nearly all major wheat producing countries in the CIS [Commonwealth of Independent States]." Racionzer said lower wheat production in major exporting countries was expected to result in a drawdown of at least 14 million mt in world inventories to 143 million mt, the lowest in 25 years. Consequently, the price of wheat has shot up to an all-time high of $343 per mt, compared to $208 per mt at the same time in 2006. "Those high prices have spilled over to other markets, impacting on the prices of most other cereals," he commented. "Higher grain prices are wearing through the food chain, increasing the cost of many basic food items, which has already led to social unrest in some countries such as Uzbekistan, Yemen and Morocco." Drought-hit Southern African countries are net importers of wheat, and in Namibia and Botswana the price of bread has almost doubled since January. But the FAO is particularly concerned over the impact of high wheat prices on Swaziland and Lesotho, which had their worst-ever harvest. "The cost of importing the wheat will put a huge strain on their economies," said James Breen, the FAO's Regional Emergency Agronomist.
Higher grain prices are wearing through the food chain, increasing the cost of many basic food items, which has already led to social unrest in some countries such as Uzbekistan, Yemen and Morocco Swaziland's annual cereal production this year was 22kg per head, while Lesotho produced 38kg per head, against an annual requirement of 180kg per head in both countries, according to the report on a joint FAO and World Food Programme crop and food supply assessment mission. Unable to access maizemeal, their staple food, the Swazis and the Basotho have had to buy bread, which has become at least 20 percent more expensive since the beginning of 2007. In South Africa the cost of wheat is 125 percent higher than it was in 2005, a local magazine, The Farmers' Weekly, pointed out. Phumzile Mdladla, who heads the Southern Africa office of the USAID-funded Famine Early Warning Systems Network (FEWS-NET), said the price of wheat had almost doubled, from $246 per mt in October 2006 to an average of $455 per mt last week, which was higher than the international price. Earlier in the year, political organisations in South Africa suggested fixing the price of bread, but this was ruled out by the government. "Food security has two legs, namely availability and affordability," said Jannie de Villiers, head of the South African Chamber of Baking, the national millers' association, who welcomed the government’s response. "The free market in agriculture has proven very successful in assuring the availability of food to all South Africans. We have, however, in the past ten years of deregulation experienced two cycles of very high food prices, which seriously impact on the affordability of food to especially the poor and vulnerable groups in our communities." The industry had not only had to contend with sharply higher wheat prices, but ever-increasing fuel costs. "The distribution cost constitutes almost a third of the total cost of baking and distributing bread," said de Villiers. "We are doing our utmost to delay passing on these huge spikes in our wheat and flour prices." The outlook According to the FAO's Racionzer, production could improve next year. "In the United States, conditions are generally favourable for fieldwork, and although planting has got off to a slower start than normal, early indications all point to the likelihood of a record area." Winter wheat crops for harvest in 2008 are already being planted.
Unable to access maizemeal, their staple food, the Swazis and the Basotho have had to buy bread, which has become at least 20 percent more expensive since the beginning of 2007 The EU has removed its 10 percent obligatory set-aside requirement for 2008, which could return up to an estimated three million hectares of arable land to production for the season, he added. Under the requirement, producers had to set aside a defined percentage of their declared areas to limit cereal production in the EU. In a press release in late September, the EU said removal of the set-aside should increase the 2008 cereals harvest by at least 10 million mt; intervention stocks have shrunk from 14 million mt at the beginning of 2006/07 to around one million mt at present. Racionzer said, "Early indications from the large producing areas in eastern Europe also suggest that farmers have intentions to plant larger wheat areas if weather and inputs allow." However, based on the latest forecasts for world production and utilisation in the FAO's latest Crop Prospects and Food Situation report, global cereal stocks, including wheat, are expected to stand at 420 million mt by the close of the seasons in 2008. This is unchanged from the reduced opening levels, and only three million mt above the 20-year low in 2004. "The food price situation is not going to improve any time soon," said the FAO's Breen

FEWS Southern Africa Food Security Outlook Oct 2007 - Mar 2008

FEWS Southern Africa Food Security Outlook Oct 2007 - Mar 2008
This report covers the period from 9/13/2007 to 10/30/2007
The FEWS NET Outlook for Southern Africa incorporates the findings from six country outlooks for the period October 2007 to March 2008. This outlook provides a basis for regional and global resource allocation and contingency planning, as well as in-country planning. This report summarizes the results of this process for Southern Africa, highlighting what FEWS NET believes are the major threats to food security in the period October 2007 to March 2008.
The most likely regional food security scenario between October 2007 and March 2008 is a continued decline in food security conditions in areas now facing moderate to high levels of food insecurity as noted above. The exception is Zimbabwe, where the situation as at end of September is expected to improve marginally between October and December, as the number of areas with high levels of food insecurity declines as a result of improvements in emergency interventions. The situation will however deteriorate again between January and March, during which the hunger season peaks, and more districts become moderately food insecure. This analysis takes into account the regional seasonal forecast which in general indicates a normal to above normal rainfall season for the period of the outlook.
The worst case scenario would arise if the assumptions under the most likely scenario do not hold, and instead, conditions deteriorate leading to extremely high levels of food insecurity, particularly in Zimbabwe and southern and central Mozambique, countries which face moderate to extreme food insecurity even in the most likely scenario. The situation would be further exacerbated if rainfall performance is poor with a delayed start and/or lengthy dry spells. Extreme levels of food insecurity will arise in parts southern Mozambique in the period October to December; while in Zimbabwe, most extreme levels would occur in the January to March 2008 period.
In Lesotho and Swaziland, where widespread food insecurity has been assessed, the situation is likely to be mitigated through on-going emergency interventions targeted at vulnerable households. However adequate assistance will depend on improvements in the responses to appeals for resources by governments and humanitarian agencies. Currently the UN appeals for emergency assistance are 18 percent funded in Swaziland, and 49 percent in Lesotho.

Uganda: Forecast for 2008 - Famine, Floods, Fear And Fighting

COLUMN21 September 2007Posted to the web 21 September 2007
Timothy Kalyegira
For most of the year since about February, something strange has come over Kampala. A city, usually warm and pleasant all year round, has taken on the chilly weather often associated with high altitude western Ugandan towns like Kabale and Fort Portal.
A few of us who enjoy sleeping nude can no longer do so. We are now experiencing the much-dreaded effects of the climate change, so long forewarned about.
At the beginning of August as the rainy season started, the United Nations' Food and Agricultural Organisation, in a report, spoke optimistically about the prospects for a good food harvest in several countries of West Africa.
Sure enough the rain came. But this was not rain. It was something maniacal. When you start getting 12 inches of rain in a week, it becomes the worst of nightmares. In this case, they are worst nightmares in living memory for Africa.
The casual and often quoted remarks by some politicians from northern Uganda that should the National Resistance Movement government continue to neglect the north, it will break off and form a Nile Republic, appeared to inadvertently come to reality.
Vital bridges over rivers in Acholi and Teso have been destroyed by the greatest floods in more than 60 years, if not more. Access by road to many parts of the north has become impossible. By an act of nature, a Nile Republic virtually cut off from the rest of Uganda has been created.
The government this week declared a state of emergency. (The last time such a state was declared was in December 1969 over Buganda, in the aftermath of the attempted assassination of president Milton Obote.)
Take a look at a map and see the African countries that have most been affected by the current deluge of rain: Uganda, Mali, Rwanda, Nigeria, Ethiopia, Senegal, Chad, Ghana, Sudan, Kenya, Niger, Togo, the Gambia, Burkina Faso, Guinea-Bissau, and Mauritania.
By some strange coincidence, these are the same countries that are either in the grip of civil war, are on the verge of or in a delicate state in which civil war is always possible or live in the neighbourhood of centres of conflict.
Even away from my endless talk of a seer's predictions, more conventional sources speak much the same thing. In its annual review of the year 1984, Compton Encyclopedia stated: "In 1984 famine continued to threaten millions of Africans, particularly in the southern, eastern, and Sahelian regions of the continent....The drought damaged the economies of almost half of the continent's 51 countries and contributed to further reductions in food production."
It continues: "Forecasting the situation by 2008, the UN Economic Commission for Africa warned of 'unimaginable poverty and a proliferation of shanty town full of beggars, delinquents, and job-hunters engaged in a desperate struggle for survival.'" (Compton's Yearbook, 1985, page 5).
What does all this mean?
Already, a crisis that seldom makes front-page news has been creeping upon the world. It is the rising world food prices. As world oil prices have risen and the Middle East remained unstable, there has been a move away from fossil fuels like petroleum to increasing experimentation with fuel extracted from ethanol.
Most ethanol is taken from maize, wheat, and cow dung. Because of this, a large stock of world maize (or in American English, corn) production has been diverted to the production of ethanol.
So, the world has sought to fight high oil prices and the pollution of the earth's climate by turning to cereals --- which is now, most ironically, producing a new crisis, the shortage of food and increase in world food prices.
What are the costs of this?
In Africa, 18 countries (a third of the 53 countries) have seen their harvest devastated by massive flooding. Much of the world, from Asia to Europe and North America, has also experienced abnormal heavy rains and floods, with millions of acres of farm land destroyed.
After these massive rains will obviously come an extended period of drought and dry conditions. This means that in the next two years, even the World Food Programme will start finding it difficult to raise the emergency food it needs to help stricken areas.
Relevant Links
East Africa Climate Sustainable Development Uganda
Imagine a combination of a world food shortage, high and rising world food prices, extremes of weather that is either dust or floods, then world oil prices recently reaching new record highs of more than 83 US dollars a barrel (or drum).
To all this, add the civil wars gathering steam in or near the same 18 African countries that have been treated to a Biblical Noah-like floods and suddenly (if it had not yet occurred to you, 2008) starts looking like a year of disaster with no compare.
We are about to witness the social conditions portrayed in Charles Dickens' novels or depressing urban life, with millions of people reduced to a grim, animal-like existence.

Saturday, December 1, 2007


By Gary W. Harding
The relationship between humans and the state of the ecosystem is not only dependent upon how many people there are, but also upon what they do. When there were few people, the dominant factors controlling ecosystem state were the natural ones that have operated for millions of years. The human population has now grown so large that there are concerns that they have become a significant element in ecosystem dynamics. One of these concerns is the relationship between human activities and climate, particularly the recent observations and the predictions of global warming, beginning with the alarm sounded by W. Broecker (1975).
The relationships among humans, their activities and global temperature can be assessed by making the appropriate measurements and analyzing the data in a way that shows the connections and their magnitudes. Human population can be closely estimated and the consequences of their activities can be measured. For example, the volume of carbon dioxide, methane and nitrous oxide emissions is an indicator of human's energy and resource consumption. An examination of population size, atmospheric concentrations of these gases and global temperature relative to time and with respect to each other is presented here to demonstrate the relations among these factors.
Many of us have seen linear graphs of human population showing the enormous growth in the last two centuries. However, significant changes in population dynamics are lost in the exponential growth and long time scales. If the data are replotted on a log-population by log-time scale, significant population dynamics emerge. First, it is apparent that population growth has occurred in three surges and second, that the time between surges has dramatically shortened (Deevey, 1960).
Figure 1. Population (Log-population verses log-time since 1 million years ago). Time values on x-axis, ignoring minus sign, are powers of 10 years before and after 1975 (at 0). Vertical dashed-line at 1995. Filled circles for known values are to left of 1995 and open circles on and to right of 1995 are for projected values. (Data updated from Deevey, 1960).
Deevey's 1960 graph has been brought up to date in Figure 1 to reflect what has been learned since then. The data have been plotted relative to 1975 with negative values before 1975 and positive values thereafter. The reason for this will become clear below. The values of the time scale, ignoring the minus signs, represent powers of 10 years.
It has been argued that a population crash occurred about 65,000 years ago (-4.8, Fig. 1), presumably due to the prolonged ice-ages during the preceding 120,000 years (Gibbons, 1993). Humans came close to perishing and Neanderthal became extinct. However, by 50,000 years ago (-4.6, Fig. 1), humans had generated population mini-explosions all around the planet. Deevey's data for population size since 500 years ago have been replaced with more recent estimates taken from The World Almanac, (1992 - 1995) including population projections out to 2025. A vertical dashed-line has been placed at 1995. Filled symbols for the known values are to the left of it and open symbols on and to the right of it are for values projected into the short-term future.
The first surge coincides with the beginning of the cultural revolution about 600,000 years ago, interrupted by the population crash 65,000 years ago. Population size rebounded 50,000 years ago and then growth slowed considerably. The second surge began with the agricultural revolution about 10,000 years ago and was followed by slow growth. Deevey argued that moving down the food chain was the underlying cause of this large and rapid spurt. The timing of the present surge matches the rise of the industrial-medical revolution 200 years ago.
A relation between innovation and population growth is embedded in the log-log plot. There was rapid growth at the start of each surge. Then, growth rate slowed as people adapted to the precipitating innovations. Each surge increased the population more than 10-fold. It appears that we are nearing the end of the present surge as recent growth rates have declined. After the initial spurt, subsequent innovations did not perpetuate growth rates. The only significant innovations were those that produced the next surge. However, accumulated innovations during the surges may have played a role in the eventual decline in population growth rates. Starting with high birth and death rates, death rate declines and longevity increases, but birth rates stay high. Some time later, birth rates decline so that eventually, net births minus deaths produces slow growth. The result is a spurt in population size. When referring to the industrial revolution, this phenomenon has been called the "demographic transition". It appears that this dynamic may have occurred twice before.
The decreases in time between surges suggests that, if past behavior is the best predictor of future behavior, we are due for another surge. It may have already begun, as indicated by the upturn in the projections at the right end of the curve in Figure 1. What might the basis for another surge be? One can think of several possibilities, including the "green revolution" and the "global economy". A dominant element in past surges has been innovations in energy use (e.g., fire, descending the food-chain, beasts of burden, fossil fuels, high-energy agriculture). Thus, the development of an abundant and cheap energy source would have a profound effect. Another 10-fold (or more) surge would produce a population of 60 to 125 billion.
Figure 2. Greenhouse Gases and Mean Global Temperature (Greenhouse gas concentrations and mean global temperature verses time). Time scale same as in Fig. 1. Gas-concentration data have been normalized to the 0 to 1 scale on left: CO2 (squares) - 190 to 430 ppm; CH4 (triangles) - 600 to 2400 ppb; N2O (diamonds) - 280 to 340 ppb. Mean global temperature (circles) plotted relative to oC on right. Vertical dashed-line at 1995, horizontal dotted line at maximum CO2 concentration and global temperature over human history before 1990. Filled and open symbols same as in Fig. 1. Projections in short-term future are based upon continuation at current growth rates. (Data measured from graphs in Gribbin, 1990 and Khalil and Rasmussen, 1992).
Mean-global-temperature (MGT) is related to the concentration of greenhouse gases (carbon dioxide, methane, nitrous oxide, water vapor and other trace gases) in the atmosphere. The most prevalent greenhouse gas is carbon dioxide (CO2). It has been shown that there is a strong relation between the atmospheric concentration of CO2 and MGT over the last 160,000 years (Gribbin, 1990). It has been suspected that the burning of fossil fuels and the clearing of land has reached such proportions that these activities have precipitated a significant increase in atmospheric CO2 concentration. The concentrations of greenhouse gases in the atmosphere have been directly measured since about 1960 and have been determined over the more distant past from air-bubbles trapped in old Antarctic, Greenland and Siberian ice and from deep-sea sediments. Mean-global-temperature has also been measured directly over the last few decades. Estimates of global temperature in the distant past have been deduced from a variety of sources. From these data, the relation among atmospheric greenhouse-gas concentrations, MGT and time is illustrated in Figure 2.
The time scale in Figure 2 is the same as that in Figure 1. Because CO2, methane (CH4) and nitrous oxide (N2O) concentrations have different scales, the data have been normalized on a 0 to 1 scale on the left. For CO2 (squares; Gribbin, 1990), 0 is equivalent to 190 parts per million (ppm) and 1 is equivalent to 430 ppm. For CH4 (triangles; R. Cicerone in Gribbin, 1990), the range is 600 to 2400 parts per billion (ppb). For N2O (diamonds; Khalil and Rasmussen, 1992), the scale is 280 to 340 ppb. Mean global temperature (circles; Gribbin, 1990) has been graphed relative to the degrees-centigrade scale on the right. The vertical dashed-line is the same as that in Figure 1. The horizontal dotted-line is the highest CO2 concentration and temperature in human history before 1990. Greenhouse-gas concentrations and MGT in the short-term future are based upon continuation at the current growth rates. This will be justified in another context below.
Figure 3. Population and Global Warming (CO2 concentration and mean global temperature verses log-population) CO2 concentration (circles) and mean global temperature (squares) plotted relative to their absolute scales, ppm on the left and oC on the right, respectively. Vertical dashed line at 1995. (Data from Figs. 1 and 2)
It is clear that the concentrations of all three gases have increased exponentially since 1950 (-1.4, Fig. 2) and that MGT has done so since 1975. Carbon dioxide concentration began to rise in conjunction with the use of fossil fuels after 1850. Although methane comes from a variety of sources, including plant decay, termites and bovine flatulence, CH4 concentration rises at the same time as CO2. This is probably due to its association with fossil-fuel production. Nitrous oxide concentration does not begin to rise until 1950. At this time, the use of human-made fertilizers and internal-combustion-engine exhaust increased dramatically. Ten thousand years ago (-4, Fig. 2), MGT increased substantially just as the agricultural revolution got started. Over the previous 200,000 years, the ecosystem was dominated by ice-ages. Projected MGT in 2025 (1.7, Fig. 2) is about 17oC, 1.5oC higher than in human history prior to 1990.
We have seen in Figures 1 and 2 that recent population, atmospheric greenhouse-gas concentrations and MGT have grown exponentially over about the same time-course. The relation of CO2 and MGT relative to population size can be observed by graphing these variables as above. Figure 3 shows this graph, where the log of population replaces log-time and CO2 concentration (circles) and MGT (squares) are plotted relative to their absolute scales, ppm on the left and oC on the right, respectively. The vertical dashed-line denotes 1995, as in Figures 1 and 2. When the population reached 4 billion in 1975, the converging relation between population and the other two variables becomes apparent.
The magnitude of the relations in Figures 2 and 3 can be determined by calculating the correlation coefficient between pairs of variables. Table 1 lists these coefficients for the population, greenhouse-gas concentration and MGT variables that we have been examining. The coefficients for the relations during the industrial revolution, 1800 through 1994, are above the diagonal of the table. The coefficients since 2000 years ago through 1994 are below the diagonal. Over the past 2000 years, there is a nearly perfect correlation between the concentration of greenhouse gases and population and between the greenhouse gases themselves. However, the correlations between both population and greenhouse-gas concentrations and MGT (bottom row) are not as strong. After 1800, the latter correlations increase to near perfection (rightmost column). The conclusion from the graphs and table is that there is a strong relationship among population size since 1800, greenhouse-gas concentrations and MGT.
TABLE 1. Correlation coefficients among population size, atmospheric greenhouse-gas concentrations and mean global temperature (1800 through 1994 above the top-left to bottom-right diagonal, n=10; 2000 years ago through 1994 below the diagonal, n=15).
Pop CO2 CH4 N2O Temp
Pop .996 .984 .977 .916
CO2 .990 .994 .974 .942
CH4 .991 .992 .949 .945
N2O .959 .943 .942 .932
Temp .718 .716 .728 .829
Determining that there is a strong relation between population size and global warming does not tell us what the underlying mechanisms are. However, documentation of the relationship between human activities and the release of greenhouse gases produces a strong inference that population size and global warming are closely related (Gribbin, 1990).
Forecasting the future is risky business. Growth rates for greenhouse-gas concentrations and MGT could decline from those at present due to unanticipated innovations or natural events. For example, volcanoes can spew enough ash into the atmosphere to block sunlight and temporarily reduce MGT slightly. However, short-term continued growth at current rates is probably an underestimate. Although population growth rate has slowed, the population is still growing. The dominating factor is that per-capita energy and resource consumption rates are increasing much faster than the population. This is not only due to anticipated increases in standards of living in underdeveloped countries, but also to future increases in the demand for energy in the developed countries (e.g., air conditioning) as summer temperatures rise. Since most of the energy will come from fossil fuels, at least for the next few decades, we can expect the atmospheric concentrations of greenhouse gases and MGT to rise in the short-term future at a faster rate than they have recently. As MGT rises, water vapor, another greenhouse component, will become a more and more significant factor due to increased evaporation.
Although a 1.5oC increase in MGT above where we were in 1990 (1990 to 2025 in Fig. 2) does not seem like much of a change, it is enough to precipitate major changes in climate. A 1.5oC drop in MGT from where we were in 1990, for example, would put the ecosystem on the verge of an ice-age. Already, there is a suspicion that, since 1975, the persistent El Nino is the first sign of the relation between global warming and climate (Kerr, 1994). As MGT increases further, we can expect more frequent and severe hurricanes and perpetual summertime droughts in many places, particularly in the US Midwest. Paradoxically, more intense winter storms will occur in some places and climatic conditions for agriculture will improve in some areas, such as in Russia (Gribbin, 1990; Bernard, 1993).
There has been considerable debate over the ecosystem's carrying capacity for humans. If we define that carrying capacity as the level that the ecosystem can support without changing state more than it has over the duration of human history, then Figures 2 and 3 indicate that we exceeded that capacity in 1975. This is the point in time where exponential growth began to push MGT along a path which has taken it outside the previous range. This does not necessarily mean that humans could not survive if MGT is about 2oC higher than it has ever been in their history. However, we will have to adapt to a radically different climate pattern and, if MGT goes any higher than that, there could be disastrous problems.
If MGT continues to increase beyond 2025 to 4oC above that in 1990, high-northern-latitude temperatures could be as much as 10oC higher than at the equator. The Arctic ice-cap would begin to melt and the permafrost under the tundra would start thawing out. As a consequence, a thick layer of rotting peat would contribute further to atmospheric CO2 and CH4 concentrations (Gribbin, 1990). With a number of human-made and natural positive-feedback elements in operation simultaneously, a threshold could be crossed (Meyers, 1995; Overpeck, 1996). Are these risks that we should be willing to take for the sake of short-term gains?
Bernard, H. W. Jr., "Global Warming Unchecked", Indiana Univ. Press, Bloomington, 1993
Broecker, W., Science, 189:460, 1975
Deevey, E. S., Scientific American, 203:195, 1960
Gibbons, A. , Science, 262:27, 1993
Gribbin, J. , "Hothouse Earth", Grove Weidenfeld, New York, 1990
Kerr, R. A., Science, 266:544, 1994
Khalil, M. A. K. and R. A. Rasmussen, J. Geophys. Res., 97:4651, 1992
"The World Almanac", Pharos, New York, 1992 - 1995
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Post Script
After this document was written (about a 2 years ago), two books came out which provide much more detail relevant to some of these issues:
HOW MANY PEOPLE CAN THE EARTH SUPPORT? by Joel E. Cohen; Norton, 1995.
DIVIDED PLANET: THE ECOLOGY OF RICH AND POOR by Tom Athanasiou; Little Brown, 1996.
Both are superbly done and provide a much more comprehensive and up to date treatment of the population and economic topics included here.
Recent evidence (Mora et al.; SCIENCE 271:1105, 1996) indicates that the possibility of a "greenhouse runaway" on Earth is much more remote than indicated at the end of the previous version of this document. Therefore, the former apocalyptic ending has been changed. Although the data presented points to a catastrophic conclusion, this was (perhaps) an overstatement of the case.