Environmental Law Prof Blog

Nanotoxicology

Science published an interesting review today, arguing that the nature of nanomaterials requires a different toxicology and that research concerning the toxicity of nanotechnology is urgently needed. Abstract  Nanotoxicity Full Article

Oil: abundance or scarcity

Roger Stern argues in an open access article published January 31, 2006 in Proceedings of the National Academy of Science that oil is abundant, but for the monopoly power of OPEC, and that fear of the "Oil Weapon" has led us to a counterproductive policy of appeasement of OPEC and Arab States -- heightening tensions in the region and funding terrorism:

oil market power, not oil per se, creates instability in the Persian Gulf. More simply, each firmstate's monopoly proceeds are a potential war prize to another. This intrinsic threat latent in monopoly price remains obscure to U.S. policymakers but is clear enough to Gulf states themselves. Their rents at risk of capture both allow and compel them to sustain some of the world's highest military spending per capita. Iran's nuclear weapons program and Iraq's assembly of the world's fourth-largest armed forces in 1990 exemplify this association of hypermilitarization and market power.

Link: Oil market power and United States national security.

Copper is an Exhaustible Resource

Original post: 1/18/06
A study published in the Proceedings of the National Academy of Sciences indicates that, if the world's population consumed copper at the rate of current consumption in North America, world copper reserves would be wholly exhausted by the middle of this century. Science   

Of course, they won't...the rate of consumption will never reach North American consumption...traditional natural resource economics assures us that prices will increase, demand will be reduced, and substitutes will be found.

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But those of us who are less sanguine about the ability of the market to achieve these goals at the right time to avoid disruptions or who do not believe the market will allocate strategic minerals optimally and optimally encourage recycling / substitution might want to design a strategic minerals policy for hard rock minerals that assures equitable/strategic allocation and uses R & D and incentives to foster optimal recycling / substitution.  If you look at what we have in the US now....it is not even close to a strategic minerals policy.  Strategic minerals policy description 

Based on my experience in the last three decades, US discussion of strategic minerals policy for the most part was limited to (1) how to increase US production and (2) how to avoid cutting off imports of strategic minerals from countries that violate human rights (i.e. anti-apartheid trade restrictions and strategic minerals exception).

Perhaps, we need a serious minerals policy -- in lieu of the never-ending battle over the resource gifts bestowed on foreign businesses by the General Mining Act.  For an example of the preoccupation with the General Mining Act and environmental protection, see National Mining Association Position on National Mining Policy, American Geological Institute Policy Brief on Mining , ELI Mining Center Description , and Earthworks. 

I understand that these issues are important.  Among other things, subsidies foster overconsumption of scarce strategic resources -- below-market valuation of minerals and unincorporated externalities are the economic sins of the General Mining Act and poor environmental protection policies. 

But, the US policy analysis needs to be broadened beyond those two issues -- which are divisive battlegrounds.  Someone should be looking toward the future.  How do we allocate our limited copper to the best uses?   How do we foster responsible metals recycling?  How do we encourage renewable substitutes?  How do we bridge the strategic gap between real world shortages that may occur and the market solutions to shortage (disruptive price spikes)?  These are policy questions that should be answered.

Updated 2/2/06:

Here are excerpts from the PNAS article by Gordon, et al, "Metal stocks and sustainability:"

 

Published online before print January 23, 2006, 10.1073/pnas.0509498103                
PNAS | January 31, 2006 | vol. 103 | no. 5 | 1209-1214

The relative proportions of metal residing in ore in the lithosphere, in use in products providing services, and in waste deposits measure our progress from exclusive use of virgin ore toward full dependence on sustained use of recycled metal. In the U.S. at present, the copper contents of these three repositories are roughly equivalent, but metal in service continues to increase. Providing today's developed-country level of services for copper worldwide (as well as for zinc and, perhaps, platinum) would appear to require conversion of essentially all of the ore in the lithosphere to stock-in-use plus near-complete recycling of the metals from that point forward....  The fraction of the stock of recoverable resources in the lithosphere already placed in use or in wastes from which it will probably never be recovered is currently 26% for copper and 19% for zinc. We lack data, but suggest that similar proportions apply for the other industrially important, geochemically scarce metals. Because the remaining stocks of ore are large compared with current needs, prices of these metals do not yet reflect scarcity value. Additionally, improved extraction techniques have kept the average real prices of these metals nearly steady for over 50 years. There is no immediate concern about the capacity of mineral resources to supply requirements for the geochemically scarce metals. Limitations would arise only from restrictions on international trade or legislative restrictions related to the environmental consequences of mining, milling, and smelting lower-grade ores. Nonetheless, over time the widespread adoption of certain new technologies can be expected to encounter natural limitations in cases for which a particular material provides a unique service. We identify platinum as the most likely metal to face this limitation because of its unique catalytic properties and its desirability for such applications as alloys for high-temperature service. 

Data on the stock of copper used in the U.S. over the past century cast doubt on the idea that demand for metals eventually decreases as incomes rise. Although the nation's GDP has increased much faster than the copper stock-in-use, the rate of increase of the per-capita copper stock remains undiminished. We find that the per-capita copper committed to some services has decreased in the 20th century but that this decrease is overbalanced by the provision of new services. The demand for new services is deeply embedded in a western popular and political culture that sees growth and development as absolutes, quickly converting services originating as luxuries or entertainments for the wealthy into necessities for everyone. Scenarios depicting future use of copper resources anticipate worldwide spread of the metal services enjoyed by the postindustrial nations. These scenarios need to explicitly address the cultural factors that continue to increase the per-capita use of copper in wealthy societies and the use of alternative materials to provide copper services. 

Concern about the extent of mineral resources arises when the stock of metal needed to provide the services enjoyed by the highly developed nations is compared with that needed to provide comparable services with existing technology to a large part of the world's population. Our stock data demonstrate that current technologies would require the entire copper and zinc ore resource in the lithosphere and perhaps that of platinum as well. Even a lower level of services could not be sustained worldwide because a continuing supply of new metal is needed to make up for inevitable losses in the recycling of the metal stock-in-use. Substitution has the potential to ameliorate this situation, but one should not automatically assume that technology will produce a satisfactory substitute for every service at an affordable price and precisely when needed. 

The topic of resource constraints inevitably recalls the classic bet between Julian Simon and Paul Ehrlich in 1980, in which Ehrlich bet that the prices of five metals would increase by 1990. Instead, the grouped prices fell, and Ehrlich paid Simon $576.07 to settle the wager. Unlike Ehrlich, we do not imply that metal price is a satisfactory measure of the remaining amount of a resource. Rather, we merely point out the present state of affairs: that anthropogenic and lithospheric stocks of at least some metals are becoming equivalent in magnitude, that worldwide demand continues to increase, and that the virgin stocks of several metals appear inadequate to sustain the modern "developed world" quality of life for all Earth's peoples under contemporary technology. These facts compel us to ask two key questions: Do we really envision a developed world quality of life for all of the people of the planet? and If so, are we willing to encourage the transformational technologies that will be required to make that vision a reality? 

Notwithstanding the answers to the key questions posed above, it is clear that, as the proportion of the stock of ore remaining in the lithosphere diminishes relative to the stock-in-use and the stock dissipated, scarcity value will indeed eventually raise the real prices of the geochemically scarce metals and will stimulate intensive recycling well above today's levels. We anticipate that price increases are unlikely to trigger a lower rate of increase in metal services or sudden economic disruption. More likely, we will see a new engineering emphasis on using these metals more efficiently and increased use of abundant alternative materials, principally iron and its alloys, aluminum, and magnesium. We anticipate a gradual transition to reliance on these alternative materials, with the use of the scarce metals increasingly restricted to those services most difficult to obtain by material substitution.

Avoiding Dangerous Climate Change

Science reported today on Avoiding Dangerous Climate Change, the book recently released based on materials from the Exeter Conference held last year.  The full report and an executive summary are available from UK's DERFA.  Executive Summary.

Here's Science's take:

CAMBRIDGE, U.K.--As climate change climbs up the political agenda, researchers have pooled much of the most recent research into what many believe is a compelling case for the immediacy of global warming.

This week's report, based on a meeting convened last year at the request of U.K. Prime Minister Tony Blair, warns of catastrophic consequences if steps are not taken now. It says a range of measures, from emissions trading to nuclear power, are needed to both minimize future impacts and cope with those that cannot be avoided. "It is clear from the work presented that the risks of climate change may well be greater than we thought," says Blair in a foreword to the report. "The U.K. government is taking this issue very seriously," says glaciologist David Vaughan of the British Antarctic Survey, "and it's nice to see the government consulting scientific opinion."

During 2005, Blair was both chair of the G8 leaders of industrial powers and president of the European Union and pledged to use his twin roles to combat global poverty and climate change. To advance the climate initiative, 200 researchers from across the globe met at the Hadley Centre for Climate Prediction and Research in Exeter last February. The meeting came 4 years after the last assessment report from the Intergovernmental Panel on Climate Change (IPCC)--the benchmark for global warming--and the scientists chewed over new results. "It was a good time to take stock," says steering committee chair Dennis Tirpak, head of the climate change unit at the Organisation for Economic Co-operation and Development in Paris.

According to the meeting report, "compared to the [IPCC's 2001 assessment], there is greater clarity and reduced uncertainty about the impacts of climate change." The report contains models showing how the acidity of the oceans will increase as a result of more carbon dioxide in the atmosphere. It also forecasts a 1000-year rise in sea levels as a result of thermal expansion of the oceans and melting of the Greenland and Antarctic ice sheets, even if greenhouse gas emissions are stabilized. "Once peripheral melting is under way around Greenland," Vaughan says, "the ice sheet may enter a state where it can't sustain itself."

Tirpak says politicians need to realize that time is running out and that the next generation may live on a planet that has no icecaps in the summer months. "It will be a profoundly different world, and we cannot imagine what that will mean," he says. "Do you want to risk the consequences?"

The Impacts of Sea Level Change on Wildlife Refuges

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    The US Fish and Wildlife Service reports that University of Maryland graduate students, working with the National Wildlife Refuge System, have developed a computer model that predicts the impacts of rising sea levels on national wildlife refuges.
    Graduate students from the university’s Sustainable Development and Conservation Biology Program estimate that sea level rise threatens the loss of 22 percent of the world’s coastal wetlands by 2080. The U.S. Fish and Wildlife Service is responsible for about 1 million acres of coastal wetlands across 159 coastal refuges.
    The results from the new computer model, called Zone Inundation and Marsh Migration, could well be an important step in helping national wildlife refuge staff decide how to protect and manage the wetlands they manage. The result also could help the U.S. Fish and Wildlife Service decide where to expand national wildlife refuges in order to continue providing wildlife habitat. The computer model offers four methods of analysis: regional context, diagnosis of present marsh conditions, prediction of changes in marsh zones, and analysis of long-term marsh changes.

Local action on global warming

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When the Kyoto Protocol came into force, Mayor Greg Nickels of Seattle challenged mayors across the country to join Seattle in taking local action to reduce global warming pollution. He recruited 10 mayors representing more than 3 million Americans issued a challenge to other American cities to  take additional actions to significantly reduce global warming pollution and a few months ago, the U.S. Conference of Mayors unanimously adopted the

 Mayors Climate Protection Agreement.  Resolution and Agreement unanimously by the U.S. Conference of Mayors.  As of  today,

202 mayors     representing over 41 million Americans have accepted the challenge.

Environmental Appeals Board Approves Animal Feeding Operation Consent Agreements

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EPA's Environmental Appeal Board has approved the first batch of consent agreements between animal feeding operations and the Agency concerning CAA and CERCLA 103 violations.   The consent agreements are a small portion of the consent agreements that will  cover more than 6,700 farms in 42 states,ranging from small dairy operations with perhaps five dozen cows to huge hog and dairy operations with tens of thousands of animals.  The farms will monitor soot and volatile organic compounds, under the Clean Air Act, and ammonia and hydrogen sulfide under the CERCLA 103 emergency reporting provision.  The data will be used to tailor

clean air, hazardous waste and emergency reporting laws for the operations and the farms agree to follow those laws after the data are collected. Each operation pays $2,500 into an E.P.A. fund, which will pay for two years of air monitoring at 28 to 30 farms nationwide. 

Companies also would have to agree to pay civil penalties of $200 to $100,000, depending on the size and number of farms they operate. Those fines would cover presumed violations, past and present.

  New Deal Eases Fines for Farms That Pollute - New York Times.

NASA's Gag Order

For reaction to NASA's gag order on Dr. James Hansen, see NASA's press office gone too far?

ABA Teleconference: EPA’s Rule on Protections for Subjects in Human Testing

The EPA Rule issued last week on human testing will be the subject of an ABA SEER teleconference.   EPA’s Rule on Protections for Subjects in Human Testing.

Happy World Wetlands Day!

Today is the anniversary of the signing of the Ramsar Convention on Wetlands.  The IUCN has a story celebrating World Wetlands Day, with important wetlands links.  World Wetlands Day

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The remainder of this post is drawn in part from

the European Commission DG Environment's excellent Science for the Environment service -- which today noted

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the recent release of 5th Millennium Ecosystem Assessment report on Wetlands and Water.

The MA report was launched in November 2005 by Secretary General, Ramsar Convention on Wetlands, Peter Bridgewater at the COP9 of the Ramsar Convention. “Ecosystems & Human Well-being: Wetlands & Water Synthesis”.  Bridgewater noted “The degradation and loss of wetlands is more rapid than that of other ecosystems. Similarly, the status of both freshwater and coastal wetland species is deteriorating faster than those of other ecosystems.” 

The MA report covers a wide range of wetland ecosystems including rice-fields, estuaries mangroves, seagrass beds, lakes, rivers, marshes, and coastal regions to a depth of 6 meters at low tide level.

    The main findings of the report are:

1. Wetlands are estimated to cover a minimum of 1,280 million hectares on a global scale.

2. Wetland ecosystems provide many services that contribute to human well-being and poverty alleviation. The most important ones include fish supply, water availability, water purification and detoxification of wastes, climate regulation, mitigation of climate change, and flood regulation.

3. More than 50% of wetlands in the developed countries were destroyed during the 20th century. Many types of wetlands worldwide continue to be degraded, converted, or lost, even though benefits gained from maintaining them are often greater than the benefits associated with their conversion.
4.  Wetlands provide many non-marketed and marketed  benefits. The total economic value of unconverted wetlands is often greater than converted wetlands. For instance, in Canada, areas of intact freshwater marshes have a total economic value of $58,000 per hectare compared with $2,400 when drained marshes are used for agriculture.
5. The degradation and loss of wetlands and wetland species is more rapid than those from other ecosystems.
6. The primary direct drivers of wetland lost or degradation are development-related conversion of coastal ecosystems, leading to large-scale losses of habitats and services.
7. Other drivers include diversion of freshwater flows, nitrogen loading, overharvesting, changes in water temperature, and species invasions.
8. The primary indirect drivers of change have been the growth of human populations in coastal areas coupled with  growing economic activity.
9. Global climate change and eutrophication are expected to aggravate the loss and degradation of many wetland ecosystems with adverse effects on human populations.   

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The report suggests implementing cross-sectoral and ecosystem-based approaches to wetland management (e.g. basin-scale management and integrated coastal zone management), rather existing sectoral approaches.  The main measures required to manage wetlands in a sustainable manner are:

• Slowing and adapting to climate change
• Slowing global growth in nutrient loading
• Greater investments in agricultural science and technology and natural resource management
• Strict regulation of marine fisheries, especially with regards to fishing quotas
• Reducing the detrimental environmental impacts of aquaculture
• Payments for ecosystem services provided by watersheds
• Development of water markets and water pricing

For more, see the MA Report on Wetlands and Water

Sustainable Agriculture Increases Yields

EU Science for Environment Reports:

Sustainable Agriculture Increases Crop Yields    

Unsustainable     agricultural practices have been recognised as key drivers of environmental     degradation at the global scale. Thus, promoting agricultural     sustainability by the use of technologies and practices that improve food     productivity without causing environmental damage is crucial in our pursuit     for a more sustainable and equitable development in

Europe

and globally.

   

In one of the     largest analysis of sustainable agricultural practices in developing     countries, an international group of scientists has examined 286 completed     and ongoing sustainable farming projects in 57 countries. In total, 37 million     hectares (3% of the cultivated area in developing countries) and some 12     million farmers were engaged in transition towards resource-conserving     agricultural practices. These included integrated pest and nutriment     management, conservation tillage, agroforestry, water harvesting, and     livestock and aquaculture integration in farming systems. Questionnaires     and published reports by project have been used in order to assess adoption     of sustainable practices and changes in yield production over time.

   

For the 360     reliable yield comparisons, the analysis has shown an average increase in     crop yields by around 64% since the 1990s. Half of the projects have shown     yield increases between 18 and 100% and 25% of the projects showed 100%     increase in yields. However, important differences have been noted between     various crops. Cotton and rice showed the lowest increases, while maize,     potatoes and some legumes (beans, pigeon peas, and others) demonstrated     more than 100% increases.

   

Though many technologies     and practices have been used in these “success projects”, the     authors suggest that the following three types of technological     improvements have probably played substantial roles in food production     increases:

   

1. More efficient water use;
    2. Improvement in organic matter accumulation and carbon sequestration; and
    3. Reduced pesticide use.

   

The paper notes     that all crops showed water use efficiency gains with the highest     improvement observed in rainfed crops. This is due to increase in water     productivity (i.e. kg of food per unit of water) as a result of certain     sustainable agricultural practices, viz. removing limitations on     productivity by increasing soil fertility; reducing soil evaporation     through conservation tillage; using more water efficient varieties;     reducing water losses to unrecoverable sinks.

   

By increasing     carbon sinks in soil organic matter and above-ground biomass, the farmers     have increased the amount of sequestered carbon by an average of 0.35     tonnes C/ha per year.

   

Regarding the analysis     of pesticide-use practices, 77% of projects with reliable pesticide-use     data have shown a decline in pesticide application by 71% while crop yields     grew by an average of 42%.

   

The authors     agree that in spite of the fact that sustainable agriculture alone will not     solve the problem of hunger and poverty in developing countries, their     findings give grounds for optimism. They also recall that the challenge     lays in finding the ways to improve the farmers’ access to     resource-conserving practices through international collaboration and     support.

   

Source: Pretty     J.N. et al. (2006)     “Resource-Conserving Agriculture Increases Yields in Developing     Countries”, Environmental Science and Technology on-line.
    Contact:     jpretty@essex.ac.uk

   

 

Open Thread

Please feel free to post comments relevant to environmental law, natural resources law, or sustainability.

One recent comment concerned hunting of wildlife on public lands in New South Wales.  See  Comment

President Still Gets a Failing Mark on Global Warming Policy

After last night's State of the Union speech, it appears that President Bush still doesn't get it.  ABC News on Global Warming and State of the Union

Another Way to Beat USN&WR Rankings

Indiana has published a symposium on the next generation of law school rankings.  See this discussion of the symposium.  Law School Rankings Symposium.  There's more than one way to skin a cat!

ELI Student Writing Competition -- Deadline Nears

The deadline for the Environmental Law Institute's first Endangered Environmental Laws Student Writing Competition (April 14, 2006) is fast approaching. ELI hopes to receive entries from as many law students as possible. More details about the competition can be found on ELI's web page, at http://www2.eli.org/writingcontest.htm. If you have any questions, please contact Lisa Goldman at 202-939-3863 or goldman@eli.org. We look forward to receiving your entries!

 

Global Warming Science: Arctic Tundra Changes Attributable to Global Warming

In a cover story of the Proceedings of the National Academy of Sciences  (published before print on January 20, 2006) and published today (vol 103, no. 5, 1342-1346), Walker et all. report that recent changes in tundra ecosystems are responses to global warming.   The article is a metaanalysis of experimental data in 11 locations as part of the International Tundra Experiment.  Experimental data confirms that warming the tundra ecosystem 1 - 3 degrees increases scrub cover, decreases moss and lichen cover, and decreases species diversity and evenness.  Abstract:

 

Recent observations of changes in some tundra ecosystems appear to be responses to a warming climate. Several experimental studies have shown that tundra plants and ecosystems can respond strongly to environmental change, including warming; however, most studies were limited to a single location and were of short duration and based on a variety of experimental designs. In addition, comparisons among studies are difficult because a variety of techniques have been used to achieve experimental warming and different measurements have been used to assess responses. We used metaanalysis on plant community measurements from standardized warming experiments at 11 locations across the tundra biome involved in the International Tundra Experiment. The passive warming treatment increased plant-level air temperature by 1-3°C, which is in the range of predicted and observed warming for tundra regions. Responses were rapid and detected in whole plant communities after only two growing seasons. Overall, warming increased height and cover of deciduous shrubs and graminoids, decreased cover of mosses and lichens, and decreased species diversity and evenness. These results predict that warming will cause a decline in biodiversity across a wide variety of tundra, at least in the short term. They also provide rigorous experimental evidence that recently observed increases in shrub cover in many tundra regions are in response to climate warming. These changes have important implications for processes and interactions within tundra ecosystems and between tundra and the atmosphere.

Another Thought -- Stop Collaborating with US News and World Report

Rosa Brooks some day may be as well known to the American legal academy as Rosa Parks is to the global community.  She wrote a post at the end of December arguing that tenured law professors should stop writing law review articles.  Goodbye

I have another liberating thought -- and I actually put it into action this year.  I received the U.S. News  & World report survey on the best environmental law programs -- and I threw it in the trash.  I received a second and a third -- I threw them in the trash.

U.S. News & World report has done virtually infinite damage to the legal academy.  It is time that we stopped collaborating with them.  It may be impossible for law schools to refuse to fill out the questionnaires -- but we could deprive them of a large part of their value by withholding our opinions.  And, even more radically, by writing those in the legal profession and urging that they withhold their opinions.

Mixed Reaction to Bush Administration Gagging Climate Scientist

Letters in the NYTimes indicate the mixed reaction to the Administration's attempt to restrict policy oriented remarks of its senior climate scientist Dr. James Hansen.Scientists condemn; federal employee condones gag order

Here is the original post:

Andrew Rivkin of The NY Times reports that the Bush Administration is attempting to silence Dr. James Hansen, NASA's director of the Goddard Institute for Space Studies since he gave a speech in December at the American Geophysical Union annual meeting.  In the speech, Hansen indicated "significant emission cuts could be achieved with existing technologies, particularly in the case of motor vehicles, and that without leadership by the United States, climate change would eventually leave the earth 'a different planet.'"  NASA Public Affairs Office Attempts to Limit Media Access

The Times coverage gives details about the attempt to gag Hansen:

The top climate scientist at NASA says the Bush administration has tried to stop him from speaking out since he gave a lecture last month calling for prompt reductions in emissions of greenhouse gases linked to global warming.

The scientist, James E. Hansen, longtime director of the agency's Goddard Institute for Space Studies, said in an interview that officials at NASA headquarters had ordered the public affairs staff to review his coming lectures, papers, postings on the Goddard Web site and requests for interviews from journalists.

Dr. Hansen said he would ignore the restrictions. "They feel their job is to be this censor of information going out to the public," he said.

Dean Acosta, deputy assistant administrator for public affairs at the space agency, said there was no effort to silence Dr. Hansen. "That's not the way we operate here at NASA," Mr. Acosta said. "We promote openness and we speak with the facts."

He said the restrictions on Dr. Hansen applied to all National Aeronautics and Space Administration personnel. He added that government scientists were free to discuss scientific findings, but that policy statements should be left to policy makers and appointed spokesmen.

Mr. Acosta said other reasons for requiring press officers to review interview requests were to have an orderly flow of information out of a sprawling agency and to avoid surprises. "This is not about any individual or any issue like global warming," he said. "It's about coordination."

Dr. Hansen strongly disagreed with this characterization, saying such procedures had already prevented the public from fully grasping recent findings about climate change that point to risks ahead.

"Communicating with the public seems to be essential," he said, "because public concern is probably the only thing capable of overcoming the special interests that have obfuscated the topic."

Dr. Hansen, 63, a physicist who joined the space agency in 1967, directs efforts to simulate the global climate on computers at the Goddard Institute in Morningside Heights in Manhattan.

Since 1988, he has been issuing public warnings about the long-term threat from heat-trapping emissions, dominated by carbon dioxide, that are an unavoidable byproduct of burning coal, oil and other fossil fuels. He has had run-ins with politicians or their appointees in various administrations, including budget watchers in the first Bush administration and Vice President Al Gore.

In 2001, Dr. Hansen was invited twice to brief Vice President Dick Cheney and other cabinet members on climate change. White House officials were interested in his findings showing that cleaning up soot, which also warms the atmosphere, was an effective and far easier first step than curbing carbon dioxide.

He fell out of favor with the White House in 2004 after giving a speech at the University of Iowa before the presidential election, in which he complained that government climate scientists were being muzzled and said he planned to vote for Senator John Kerry.

But Dr. Hansen said that nothing in 30 years equaled the push made since early December to keep him from publicly discussing what he says are clear-cut dangers from further delay in curbing carbon dioxide.

In several interviews with The New York Times in recent days, Dr. Hansen said it would be irresponsible not to speak out, particularly because NASA's mission statement includes the phrase "to understand and protect our home planet."

He said he was particularly incensed that the directives had come through telephone conversations and not through formal channels, leaving no significant trails of documents.

Dr. Hansen's supervisor, Franco Einaudi, said there had been no official "order or pressure to say shut Jim up." But Dr. Einaudi added, "That doesn't mean I like this kind of pressure being applied."

The fresh efforts to quiet him, Dr. Hansen said, began in a series of calls after a lecture he gave on Dec. 6 at the annual meeting of the American Geophysical Union in San Francisco. In the talk, he said that significant emission cuts could be achieved with existing technologies, particularly in the case of motor vehicles, and that without leadership by the United States, climate change would eventually leave the earth "a different planet."

The administration's policy is to use voluntary measures to slow, but not reverse, the growth of emissions.

After that speech and the release of data by Dr. Hansen on Dec. 15 showing that 2005 was probably the warmest year in at least a century, officials at the headquarters of the space agency repeatedly phoned public affairs officers, who relayed the warning to Dr. Hansen that there would be "dire consequences" if such statements continued, those officers and Dr. Hansen said in interviews.

Among the restrictions, according to Dr. Hansen and an internal draft memorandum he provided to The Times, was that his supervisors could stand in for him in any news media interviews.

Mr. Acosta said the calls and meetings with Goddard press officers were not to introduce restrictions, but to review existing rules. He said Dr. Hansen had continued to speak frequently with the news media.

But Dr. Hansen and some of his colleagues said interviews were canceled as a result.

In one call, George Deutsch, a recently appointed public affairs officer at NASA headquarters, rejected a request from a producer at National Public Radio to interview Dr. Hansen, said Leslie McCarthy, a public affairs officer responsible for the Goddard Institute.

Citing handwritten notes taken during the conversation, Ms. McCarthy said Mr. Deutsch called N.P.R. "the most liberal" media outlet in the country. She said that in that call and others, Mr. Deutsch said his job was "to make the president look good" and that as a White House appointee that might be Mr. Deutsch's priority.

But she added: "I'm a career civil servant and Jim Hansen is a scientist. That's not our job. That's not our mission. The inference was that Hansen was disloyal."

Normally, Ms. McCarthy would not be free to describe such conversations to the news media, but she agreed to an interview after Mr. Acosta, at NASA headquarters, told The Times that she would not face any retribution for doing so.

Mr. Acosta, Mr. Deutsch's supervisor, said that when Mr. Deutsch was asked about the conversations, he flatly denied saying anything of the sort. Mr. Deutsch referred all interview requests to Mr. Acosta.

Ms. McCarthy, when told of the response, said: "Why am I going to go out of my way to make this up and back up Jim Hansen? I don't have a dog in this race. And what does Hansen have to gain?"

Mr. Acosta said that for the moment he had no way of judging who was telling the truth. Several colleagues of both Ms. McCarthy and Dr. Hansen said Ms. McCarthy's statements were consistent with what she told them when the conversations occurred.

"He's not trying to create a war over this," said Larry D. Travis, an astronomer who is Dr. Hansen's deputy at Goddard, "but really feels very strongly that this is an obligation we have as federal scientists, to inform the public."

Dr. Travis said he walked into Ms. McCarthy's office in mid-December at the end of one of the calls from Mr. Deutsch demanding that Dr. Hansen be better controlled.

In an interview on Friday, Ralph J. Cicerone, an atmospheric chemist and the president of the National Academy of Sciences, the nation's leading independent scientific body, praised Dr. Hansen's scientific contributions and said he had always seemed to describe his public statements clearly as his personal views.

"He really is one of the most productive and creative scientists in the world," Dr. Cicerone said. "I've heard Hansen speak many times and I've read many of his papers, starting in the late 70's. Every single time, in writing or when I've heard him speak, he's always clear that he's speaking for himself, not for NASA or the administration, whichever administration it's been."

The fight between Dr. Hansen and administration officials echoes other recent disputes. At climate laboratories of the National Oceanic and Atmospheric Administration, for example, many scientists who routinely took calls from reporters five years ago can now do so only if the interview is approved by administration officials in Washington, and then only if a public affairs officer is present or on the phone.

Where scientists' points of view on climate policy align with those of the administration, however, there are few signs of restrictions on extracurricular lectures or writing.

One example is Indur M. Goklany, assistant director of science and technology policy in the policy office of the Interior Department. For years, Dr. Goklany, an electrical engineer by training, has written in papers and books that it may be better not to force cuts in greenhouse gases because the added prosperity from unfettered economic activity would allow countries to exploit benefits of warming and adapt to problems.

In an e-mail exchange on Friday, Dr. Goklany said that in the Clinton administration he was shifted to nonclimate-related work, but added that he had never had to stop his outside writing, as long as he identified the views as his own.

"One reason why I still continue to do the extracurricular stuff," he wrote, "is because one doesn't have to get clearance for what I plan on saying or writing."