Δευτέρα, Φεβρουαρίου 19, 2007

Weitzman on Stern

Some months ago, Stern Review, was published and "shocked" global community with its harsh environmental prediction, especially the cost that future generations will have to bear regarding global warming and environmental degradation. Nevertheless, the Stern Report is also a piece of pure economic analysis concerning environmental issues. And if so, we have to judge it also of its economic value. Martin Weitzman was delegated from JEL to write a paper on the Stern Review. Even though I did not have a chance to read the paper carefully, I think (from a rather quick scan) that it is pretty interesting. The resume of Weitzman is that the Stern Review may be true, but completely different reasons than that raised by Stern.

"History will judge whether the economic analysis of the Stern Review was more wrong or more right, and, if it was more right, whether as pure economic analysis it was right for the right reasons or it was right for the wrong reasons."

Παρασκευή, Φεβρουαρίου 16, 2007

Breathing Earth

By David Bleja

With all the talk of global warming, what better way to understand the pressing fragility of the planet than a real-time simulation? David Bleja's interactive map tracks carbon dioxide emissions and birth and death rates for countries throughout the world, using data from the CIA's World Factbook. As an ongoing display of symbols and red flashes pepper the map, you can scroll over countries to compare data. The site also keeps a running ticker to see how those numbers have grown since you opened the site.


Κυριακή, Φεβρουαρίου 11, 2007

Stern-Nordhaus-Dagupta debate on GW

Economist's View: Global Warming Bonds

Global Warming Bonds

Andrew Oswald has an idea for a cooler world. This is from the comments section of Martin Wolf's Economists' Forum:

Andrew Oswald: ...I believe we could and should work out a way for the next generation to pay. This is because it is those millions of unborn citizens who will benefit from a cooler world, and because doing so will solve the problem at the crux of the Stern-Nordhaus-Dasgupta debate, which is really the question: why should the current generation pay generously and pay quickly?

This means it is necessary somehow to design a way of bringing the future, with their cheque books, to the negotiating table. Here is a suggestion.

We print a government bond called a Global Warming Bond. These have stamped on them: "I pay out 1000 indexed pounds in every year - beginning in the year 2050 and going on forever". These bonds would be given out, as a subsidy, to those people and organizations who reduce emissions today.

The bonds would have immediate value. A market in them would spring up. I shall assume that their status as government bonds would make risk of default negligible. One might object to this, but I shall leave it at that.

The attractive thing about these bonds is that (leaving aside technical issues about general equilibrium reallocations across asset classes) they would be funded essentially by future taxpaying citizens. Those earning and paying taxes in 2050 onwards would fund them. Our citizens, in 2007, would gain.

In this way, the unborn would subsidize us to cut carbon emissions.

I offer this as an idea. There may be a flaw in it; one would have to think through a formal model. In economics, we are used to tax neutrality results coming back to bite us when we hope they will not. But perhaps the GW Bond idea suggests an avenue of ideas on these problems.

That's a good trick - charging future generations to prevent environmental damage that would occur before they are born and then affect them. I wonder if we can get the unborn to pay us not to do other sorts of damage, kind of a protection racket. Pay us off in bonds or we'll pollute this river! I've got a chainsaw and I'm not afraid to use it! More seriously, what do you think of this idea? There are also comments by Jeffrey Frankel, Lawrence Summers, Paul Seabright, and John Williamson.

Stiglitz on Global Warming

Comment is free: Turning tides

Turning tides

The climate change message is finally getting through; it's time for political leaders to move beyond mere rhetoric and act.
Joseph Stiglitz


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February 10, 2007 10:00 AM | Printable version

The message, it seems, has finally gotten through: global warming represents a serious threat to our planet. At the recent World Economic Forum in Davos, world leaders saw climate change, for the first time, topping the list of global concerns.

Europe and Japan have shown their commitment to reduce global warming by imposing costs on themselves and their producers, even if it places them at a competitive disadvantage. The biggest obstacle until now has been the United States. The Clinton administration had called for bold action as far back as 1993, proposing what was in effect a tax on carbon emissions; but an alliance of polluters, led by the coal, oil, and auto industries beat back this initiative.

To the scientific community, the evidence on climate change has, of course, been overwhelming for more than a decade and a half. I participated in the second assessment of the scientific evidence conducted by the Intergovernmental Panel on Climate Change, which perhaps made one critical mistake: it underestimated the pace at which global warming was occurring. The Fourth Assessment, which was just issued, confirms the mounting evidence and the increasing conviction that global warming is the result of the increase in greenhouse gases in the atmosphere.

The increased pace of warming reflects the impact of complex non-linear factors and a variety of "tipping points" that can result in acceleration of the process. For instance, as the Arctic ice cap melts, less sunlight is reflected. Seemingly dramatic changes in weather patterns - including the melting of glaciers in Greenland and the thawing of the Siberian permafrost - have at last convinced most business leaders that the time for action is now.

Recently, even President Bush seems to have woken up. But a closer look at what he is doing, and not doing, shows clearly that he has mostly heard the call of his campaign contributors from the oil and coal industries, and that he has once again put their interests over the global interest in reducing emissions. If he were truly concerned about global warming, how could he have endorsed the construction of coal-fired electricity plants, even if those plants use more efficient technologies than have been employed in the past?

What is required, first and foremost, are market-based incentives to induce Americans to use less energy and to produce more energy in ways that emit less carbon. But Bush has neither eliminated massive subsidies to the oil industry (though, fortunately, the Democratic Congress may take action) nor provided adequate incentives for conservation. Even his call for energy independence should be seen for what it is - a new rationale for old corporate subsidies.

A policy that entails draining America's limited oil supplies - I call it "drain America first" - will leave the US even more dependent on foreign oil. The US imposes a tariff of more than 50 cents per gallon on sugar-based ethanol from Brazil, but subsidises inefficient corn-based American ethanol heavily - indeed , it requires more than a gallon of gasoline to fertilise, harvest, transport, process, and distil corn to yield one gallon of ethanol.

As the world's largest polluter, accounting for roughly a quarter of global carbon emissions, America's reluctance to do more is perhaps understandable, if not forgivable. But claims by Bush that America cannot afford to do anything about global warming ring hollow: other advanced industrial countries with comparable standards of living emit only a fraction of what the US emits per dollar of GDP.

As a result, American firms with access to cheap energy are given a big competitive advantage over firms in Europe and elsewhere. Some in Europe worry that stringent action on global warming may be counterproductive: energy-intensive industries may simply move to the US or other countries that pay little attention to emissions. And there is more than a grain of truth to these concerns.

A striking fact about climate change is that there is little overlap between the countries that are most vulnerable to its effects - mainly poor countries in the South that can ill afford to deal with the consequences - and the countries, like the US, that are the largest polluters. What is at stake is in part a moral issue, a matter of global social justice.

The Kyoto Protocol represented the international community's attempt to begin to deal with global warming in a fair and efficient way. But it left out a majority of the sources of emissions, and unless something is done to include the US and the developing countries in a meaningful way, it will be little more than a symbolic gesture. There needs to be a new "coalition of the willing," this time perhaps led by Europe - and this time directed at a real danger.

This "coalition of the willing" could agree to certain basic standards: to forego building coal-fired plants, increase automobiles' fuel efficiency, and provide targeted assistance to developing countries to enhance their energy efficiency and reduce emissions. Coalition members could also agree to provide stronger incentives to their own producers, through either more stringent caps on emissions or higher taxes on pollution. They could then agree to impose taxes on products from other countries - including the US - that are produced in ways that unnecessarily add substantially to global warming. What is at stake is not protecting domestic producers, but protecting our planet.

The changing climate on climate change provides political leaders in Europe and other potential members of this "coalition of the willing" an unprecedented opportunity to move beyond mere rhetoric. The time to act is now.

© Project Syndicate, 2007.

Σάββατο, Φεβρουαρίου 10, 2007

Theory of Incentives and Global Warming

I was always convinced that incentives play the most significant role in the way that people think and act. Mainly, due to the fact that I study Economics I am prone to believe that proper incentives can guide optimal action. In this manner, I was amazed to read that Richard Branson announced a $25 million prize for the first scientist to come up with a way to extract greenhouse gases from the atmosphere. Are 25 $ million what someone could call a proper incentive? You bet it is!!!

But you know, this reminds me some ads that say "We will pay you 3.000 euros if you prove that you can find better fuels than ours"!! The reason for publishing such an ad is threefold:

1. None can ever prove such a thing.
2. None will ever bother proving it.
3. You are sincere and thus eager to pay someone who can prove it.

As a nervous economist and always suspicious of others' intentions and "utility maximizations", I wonder why someone would like to pay such a great deal of money for a thing like global warming? A merely private donation, for a merely social issue!! Who knows? It is just that I fear that this environmental madness is not as noble and pure as it seems. In any case, what I am suspicious of are only speculations. I pray time will prove me wrong. For the time being one can cast a look at CNN.com and the relevant article.

Πέμπτη, Φεβρουαρίου 08, 2007

"Global Warming and Hot Air" by Robert J. Samuelson

Washington Post
February 7, 2007

"Global Warming and Hot Air"
by Robert J. Samuelson

You could be excused for thinking that we'll soon do something serious about global warming. Last Friday, the Intergovernmental Panel on Climate Change (IPCC) -- an international group of scientists -- concluded that, to a 90 percent probability, human activity is warming the Earth. Earlier, Democratic congressional leaders made global warming legislation a top priority; and 10 big U.S. companies (including General Electric and DuPont) endorsed federal regulation. Strong action seems at hand.

Don't be fooled. The dirty secret about global warming is this: We have no solution. About 80 percent of the world's energy comes from fossil fuels (coal, oil, natural gas), the main sources of man-made greenhouse gases. Energy use sustains economic growth, which -- in all modern societies -- buttresses political and social stability. Until we can replace fossil fuels or find practical ways to capture their emissions, governments will not sanction the deep energy cuts that would truly affect global warming.

Considering this reality, you should treat the pious exhortations to "do something" with skepticism, disbelief or contempt. These pronouncements are (take your pick) naive, self-interested, misinformed, stupid or dishonest. Politicians mainly want to be seen as reducing global warming. Companies want to polish their images and exploit markets created by new environmental regulations. As for editorialists and pundits, there's no explanation except superficiality or herd behavior.

Anyone who honestly examines global energy trends must reach these harsh conclusions. In 2004, world emissions of carbon dioxide (CO2, the main greenhouse gas) totaled 26 billion metric tons. Under plausible economic and population assumptions, CO2emissions will grow to 40 billion tons by 2030, projects the International Energy Agency. About three-quarters of the increase is forecast to come from developing countries, two-fifths from China alone. The IEA expects China to pass the United States as the largest source of carbon dioxide by 2009.

Poor countries won't sacrifice economic growth -- lowering poverty, fostering political stability -- to placate the rich world's global warming fears. Why should they? On a per-person basis, their carbon dioxide emissions are only about one-fifth the level of rich countries. In Africa, less than 40 percent of the population even has electricity.

Nor will existing technologies, aggressively deployed, rescue us. The IEA studied an "alternative scenario" that simulated the effect of 1,400 policies to reduce fossil fuel use. Fuel economy for new U.S. vehicles was assumed to increase 30 percent by 2030; the global share of energy from "renewables" (solar, wind, hydropower, biomass) would quadruple, to 8 percent. The result: by 2030, annual carbon dioxide emissions would rise 31 percent instead of 55 percent. The concentration levels of emissions in the atmosphere (which presumably cause warming) would rise.

Since 1850, global temperatures have increased almost 1 degree Celsius. Sea level has risen about seven inches, though the connection is unclear. So far, global warming has been a change, not a calamity. The IPCC projects wide ranges for the next century: temperature increases from 1.1 degrees Celsius to 6.4 degrees; sea level rises from seven inches to almost two feet. People might easily adapt; or there might be costly disruptions (say, frequent flooding of coastal cities resulting from melting polar ice caps).

I do not say we should do nothing, but we should not delude ourselves. In the United States, the favored remedy is "cap and trade." It's environmental grandstanding -- politicians pretending they're doing something.

Companies would receive or buy quotas ("caps") to emit carbon dioxide. To exceed the limits, they'd acquire some other company's unused quotas ("trade"). How simple. Just order companies to cut emissions. Businesses absorb all the costs.

But in practice, no plausible "cap and trade" program would significantly curb global warming. To do that, quotas would have to be set so low as to shut down the economy. Or the cost of scarce quotas would skyrocket and be passed along to consumers through much higher energy prices. Neither outcome seems likely. Quotas would be lax. The program would be a regulatory burden with little benefit. It would also be a bonanza for lobbyists, lawyers and consultants, as industries and localities besieged Washington for exceptions and special treatment. Hello, influence-peddling and sleaze.

What we really need is a more urgent program of research and development, focusing on nuclear power, electric batteries, alternative fuels and the capture of carbon dioxide. Naturally, there's no guarantee that socially acceptable and cost-competitive technologies will result. But without them, global warming is more or less on automatic pilot. Only new technologies would enable countries -- rich and poor -- to reconcile the immediate imperative of economic growth with the potential hazards of climate change.

Meanwhile, we could temper our energy appetite. I've argued before for a high oil tax to prod Americans to buy more fuel-efficient vehicles. The main aim would be to limit insecure oil imports, but it would also check CO2emissions. Similarly, we might be better off shifting some of the tax burden from wages and profits to a broader tax on energy or carbon. That would favor more fuel-efficient light bulbs, appliances and industrial processes.

It's a debate we ought to have -- but probably won't. Any realistic response would be costly, uncertain and no doubt unpopular. That's one truth too inconvenient for almost anyone to admit.

© 2007 The Washington Post Company

Κυριακή, Φεβρουαρίου 04, 2007

Περιβάλλον και Ενέργεια

Τις τελευταίες εβδομάδες όλοι έχουμε παρατηρήσει μια στροφή του τηλεοπτικού και εκδοτικού ενδιαφέροντος στα θέματα του περιβάλλοντος και της ενέργειας. Κάτι που στο εξωτερικό συμβαίνει εδώ και χρόνια, στην Ελλάδα -πιστοί στις παραδόσεις- προτιμούμε να "μπαίνουμε" τελευταίοι στο παιχνίδι. Οι περισσότερες κυριακάτικες εφημερίδες, λοιπόν, αφιερώνουν εκτενή άρθρα για το περιβάλλον και την κλιματική αλλαγή. Ωστόσο, ενέχει ο κίνδυνος να οδηγηθούμε σε μια κλιματο-υστερία που μόνο καλό δεν μπορεί να προσφέρει (όπως έχει γίνει για την πλειοψηφία θεμάτων τέτοιου χαρακτήρα). Η φιλική περιβαλλοντική συμπεριφορά δεν είναι θέμα που μπορεί να αλλάξει σε μια μέρα. Όπως η παιδεία και η κουλτούρα, χρειάζεται χρόνο για να εμπεδωθεί και να γίνει κομμάτι της καθημερινότητας (βέβαια ουσίας είναι αν διαθέτουμε τον απαραίτητο χρόνο...). Με αυτή τη λογική πρέπει να διαβάζουμε και να προβληματιζόμαστε πάνω στα θέματα του περιβάλλοντος. Περιττό, βέβαια, να τονίσω ότι προφανώς δεν είναι όλα τα προβλήματα του σύγχρονου κόσμου απόρροια του φαινομένου του θερμοκηπίου!!! Παραθέτω, λοιπόν, μερικά από τα άρθρα αυτής της Κυριακής που μου έκαναν εντύπωση, ξεχωρίζοντας, όμως, αυτά της Ελευθεροτυπίας και του Έθνους.

Η "Κυριακάτικη Ελευθεροτυπία" αφιερώνει ένα εκτενές άρθρο στην έκθεση της IPCC (περίληψη της έκθεσης μπορεί να βρεθεί σε σχετικό πρηγούμενο link). Πολύ ενδιαφέρον όμως και το άρθρο, όσον αφορά την στροφή προς την πυρηνική ενέργεια.

Το "in.gr" αναφέρεται στην αντιμετώπιση που είχε η έκθεση από την πλευρά των χωρών που ευθύνονται κυρίως για το φαινόμενο του θερμοκηπίου.
Η "Κυριακάτικη Καθημερινή", πέρα από διάφορα άλλα άρθρα σχετικά με το περιβάλλον, αναφέρεται στη δυσχερή θέση στην οποία βρίσκεται η Ελλάδα ως προς την ενεργειακή της κατανάλωση.

Το "Έθνος της Κυριακής" έχει ένα ιδιάιτερα ενδιαφέρον και "πικάντικο" θέμα σχετικά με την έκθεση της IPCC.

Climate Change 2007

Μιας και έχει γίνει ήδη αναφορά στην έκθεση για την "Κλιματική Αλλαγή", παραθέτω και το link της pdf περίληψης της έκθεσης.

Climate Change 2007: The Physical Science Basis

Παρασκευή, Φεβρουαρίου 02, 2007

Μη αναστρέψιμη η άνοδος της θερμοκρασίας

kathimerini.gr | Μη αναστρέψιμη η άνοδος της θερμοκρασίας

Μη αναστρέψιμη η άνοδος της θερμοκρασίας

Η ΕΚΘΕΣΗ των επιστημόνων που συγκεντρώθηκαν στο Παρίσι και που αφορά τις κλιματικές αλλαγές, αναφέρει στα κύρια πορίσματα της ότι το επίπεδο της θάλασσας σε παγκόσμιο επίπεδο θα ανέβει μέχρι και 59 εκατοστά μέχρι το 2100. Επιπλέον, οι επιστήμονες δεν αποκλείουν μεγαλύτερες ανόδους εάν συνεχιστεί το λιώσιμο των πάγων στη Γροιλανδία και την Ανταρκτική.

Η άνοδος του επιπέδου της θάλασσας κατά 59 εκατοστά που αναφέρεται στην έκθεση είναι μικρότερη από την αντίστοιχη άνοδο των 88 εκατοστών που προέβλεπε αντίστοιχη έκθεση του 2001. Οι επιστήμονες εξηγούν αυτή την αλλαγή στην πρόβλεψη λόγω της καλύτερης κατανόησης και μελέτης των κλιματικών αλλαγών κατά την τελευταία πενταετία.

Ωστόσο, δεν αποκλείεται το ενδεχόμενο το νούμερο αυτό να αλλάξει εξαιτίας της έλλειψης κατανόησης σε ότι αφορά τους παγετώνες στη Γροιλανδία και την Ανταρκτική.

Η Σάρον Χέιζ, επικεφαλής της αμερικανικής αντιπροσωπείας χαρακτήρισε την έκθεση «σημαντική και χρήσιμη» για τα πολιτικούς και τα κέντρα λήψης αποφάσεων. Η κ. Χέιζ θεωρεί σημαντικό ότι το κείμενο χρησιμοποιεί τελικά αυστηρή γλώσσα καθώς και την επισήμανση ότι η άνοδος της θερμοκρασίας οφείλεται τελικά στον ανθρώπινο παράγοντα.

Η κ.Χέιζ δεν αναφέρθηκε ωστόσο στο πώς η έκθεση αυτή θα μπορούσε να επιφέρει αλλαγές στην πολιτική Μπους για τις ρυπογόνες εκπομπές αερίων. Οι πληροφορίες αναφέρουν ότι η σκληρή γλώσσα του κειμένου είναι αποτέλεσμα της προτροπής ενός Αμερικανού επιστήμονα και ότι το κείμενο διαφέρει σημαντικά από το Πρωτόκολλο του Κιότο, το οποίο οι ΗΠΑ δεν επικύρωσαν ποτέ. Ωστόσο, η κίνηση του Αμερικανού επιστήμονα δε συνεπάγεται σε καμία περίπτωση αλλαγή της πολιτικής του Λευκού Οίκου σε αυτό το σημαντικό θέμα.

Η έκθεση της Διακυβερνητικής Διάσκεψη για τις Κλιματικές Αλλαγές είναι ένα επιστημονικό κείμενο που περιγράφει την άποψη των επιστημόνων για τα τεκταινόμενα στο περιβάλλον καθώς και προβλέψεις για το άμεσο μέλλον. Η έκθεση αναφέρει ότι η διαδικασία ανόδου της θερμοκρασίας στον πλανήτη έχει ήδη ξεκινήσει, κατά πάσα πιθανότητα είναι αποτέλεσμα της ανθρώπινης επέμβασης στο περιβάλλον και δεν θα είναι δυνατό να περιοριστεί για τους επόμενους αιώνες.

IPCC report is out

Global warming called 'unequivocal' - Print Version - International Herald Tribune

International Herald Tribune
Global warming called 'unequivocal'
By Elisabeth Rosenthal and Andrew C. Revkin
Friday, February 2, 2007

In a bleak and powerful assessment of the future of the planet, the leading international network of climate change scientists concluded for the first time Friday that global warming is "unequivocal" and that human activity is "very likely" to blame. The warming will continue for hundreds of years, they predicted.

The scientists, members of the Intergovernment Panel on Climate Change, said that new science had also allowed them to conclude that the warming caused by human activity is probably influencing other aspects of climate change — including a rise in the number of heat waves, extreme storms and droughts as well as ocean warming and wind patterns.

A vast improvement in the science of climatology — including "large amounts of new and more comprehensive data" — has allowed the group to become far more confident and specific in its predictions since its last assessment, in 2001, the authors said. The conclusions were presented at a press conference in Paris, along with a summary of their much anticipated fourth report.

Until Friday, there was still the scientific possibility that the global climate change in the last 50 years could be explained by natural variation rather than man-made influences, particularly the burning of fossil fuel.

The scientists, representing 13 countries and whose work was vetted by representatives from hundreds of nations, left little doubt of where they stood.

"There is no question that this is driven by human activity," said Dr. Susan Solomon, a chairwoman of the panel that produced the report. She noted that in calling the link between people and climate change "very likely" the scientists had increased certainty on a connection from their previous estimate of 66 percent to 90 percent. "Warming of the climate system is now unequivocal, unequivocal," she said.

Achim Steiner, executive director of the United Nations Environment Program, said the report represented a tipping point in the accumulating data on climate change, even though the basic message of the document — that human activity is creating dangerous warming — had been already widely accepted in many quarters.

"Feb. 2, 2007, will perhaps be remembered as the day" when global thinking about climate change moved from debate to action, he said. "The focus will shift from whether climate change is due to human activity, to what on earth are we going to do about it."

Indeed, many of the report's authors called on governments to heed the powerful science now in hand.

"Policy makers paid us to do good science, and now we have very high scientific confidence in this work — this is real, this is real, this is real," said Richard Alley, one of the lead authors and a professor at Penn State University. "So now act, the ball's back in your court."

Climate change will cause far-flung ramifications for humans and nature, according to the 21-page summary of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, which was approved early Friday by teams of officials from more than 100 countries after three days and nights of wrangling over wording.

Even Solomon, known as a staid and conservative scientist, chose to highlight dramatic examples. If greenhouse gases, which trap heat, cause temperatures to rise 1.9 to 4.6 degrees Celsius (3.4 to 8.3 Fahrenheit) as the report predicts it might, that could lead to a sea level rise of 7 meters, or 23 feet, if the temperature rise were sustained over thousands of years, she said.

The ripple effect of the warming has devastating implications for man that will continue for centuries even if carbon emission could be stabilized at the 2000 level, because the gases persist for years. The impact that carbon emissions have had on climate has increased by 20 percent in the last 15 years, Solomon said.

The report lays out four different scenarios of global warming, depending on how humanity responds. All predict a continued rise in temperature and sea level for the next century. Temperatures will rise between 1.8 and 6.4 degrees Celsius (3.2 to 11.5 Fahrenheit) depending on the scenario. Sea levels will go up 18 to 55 centimeters, or 7 to 21 inches.

"It is very likely that hot extremes, heat waves and heavy precipitation events will continue to become more frequent," said the report.

Officials here made clear that the effects would be felt in the very near future — indeed, they are being felt now.

"If you are a South Asian child born in 2007 you may well in your lifetime be facing inundation of your lands and being turned into an environment refugee," Steiner said.

Generally, the scientists said, more precipitation will fall at higher latitudes, which are likely also to see lengthened growing seasons, while semi-arid, subtropical regions already chronically beset by drought could see a further 20 percent drop in rainfall under a midrange scenario for increases in the greenhouse gases.

But Dr. Rajendra Pachauri, a chairman of the panel, said the report was "heartening" in the sense that it gave politicians very specific information on which to act. "The science has move several steps beyond what was possible before," he said. "You see the extent to which human activity is influencing greenhouse gases. You are able to see the costs of inaction."

The panel operates under the aegis of the United Nations and was chartered in 1988 — a year of record heat, burning forests and the first big headlines about global warming — to provide regular reviews of climate science to governments to inform policy choices.

Government officials are involved in shaping the summary of each report, but the scientist-authors, who are unpaid, have the final say over the thousands of pages in four underlying technical reports that will be released later this year.

Big questions remain about the speed and extent of some impending changes, both because of uncertainty about future population and pollution trends and the complex interrelationships of the emissions, clouds, dusty kinds of pollution, the oceans and earth's veneer of life.

One big question mark involves how much arctic ice will melt and how fast, which would have a major impact on sea levels.

The report essentially caps a half-century-long scientific effort to discern whether humans, through the buildup of carbon dioxide and other gases released mainly by burning fuels and forests, could influence the earth's climate system in potentially momentous ways.

Two subsequent reports by the panel to be released this spring are to focus on how the world should respond to climate change.

One will deal with mitigation — efforts by countries to reduce the production of heat trapping gases. These include international efforts like the Kyoto Protocol as well as programs that encourage individuals to use solar heating in their homes and to take public transportation rather than driving.

The second will focus on adaptation, or how countries might respond to climate change that scientists are now sure will inevitably occur.

Should rivers be artificially widened to accommodate increased rainfall that is likely to occur in much of Europe, for example? Should dikes be reinforced to prevent flooding in low-lying cities, or is sea level rise likely to be so great that such land should be abandoned and its residents moved inland?

In two weeks, the European Union will convene a meeting in Berlin on how to adapt to changing in water conditions, like heavier rains and flooding.

Andrew C. Revkin reported from New York.

Πέμπτη, Φεβρουαρίου 01, 2007

Δραματική πτώση υδροφόρου ορίζοντα

"«Αρχή των πάντων» κατά τον Θαλή τον Μιλήσιο, δομικό στοιχείο του σύμπαντος και πρωταγωνιστής στο έργο της ζωής, το νερό είναι κάτι παραπάνω από ένα πολύτιμο φυσικό αγαθό. Σταγόνα βροχής, νιφάδα χιονιού, πάγος, πηγή, ποταμός - όταν το νερό μεταμορφώνεται, μεταμορφώνει τα πάντα, υπαγορεύει όλες τις εξελίξεις."

Ένα πολύ ωραία άρθρο της Καθημερινής και αρκετά ανησυχητικό για την έντονη φετινή ανομβρία, αλλά και αυτή που μας επιφυλάσουν τα χρόνια που έρχονται.