NPCA: Climate Change Greatest Threat Facing the National Park System

Climate change could rid Joshua Tree National Park of joshua trees. NPS photo by Dar Spearing.

When you think about threats to national parks, you can point to air pollution, water pollution, development on a park's boundaries, and genetic bottlenecks affecting a park's wildlife. But few people seem to think about climate change.

Indeed, climate change is neither sexy nor glamorous, and judging from how many folks read Traveler posts about climate change and the parks, not too many folks care to hear about it. Well, the National Parks Conservation Association wants you to start thinking about it.

During a House subcommittee meeting held in California today, NPCA representatives testified that their organization views climate change as the "greatest threat" to the national parks. Indeed, researchers predict Glacier National Park will lose all of its glaciers within 20 years, and some models suggest Joshua Tree National Park will have no living Joshua trees left within a century.

During this morning's field hearing, held just outside Joshua Tree, NPCA's California Desert Office program manager, Mike Cipra, told the representatives that national parks are already showing the effects of climate change. Some are seeing less snow and rainfall, others are dealing with increased pests and disease, some are being confronted by abnormal flooding and fires, and there's a shift in the habitat ranges of plants and animals, he said.

The bottom line, said Mr. Cipra, is that Congress needs to provide funding to help wildlife and ecosystems adapt to climate change while also taking steps to slow global warming by limiting greenhouse gas emissions.

He said NPCA supports providing the National Park Service with a dedicated funding stream for this need, such as could be provided from a percentage of profits raised by the sale of carbon pollution allowances under a cap-and-trade policy. Such funding would allow land managers to plan long-term and ecosystem-wide instead of making piecemeal changes with limited effect, he said. The cost would be far outweighed by the economic benefits of having working ecosystems and protecting keystone species, added Mr. Cipra.

"As Americans, we have faced tremendous environmental challenges before," the NPCA representative testified. "We met these challenges with courage, with urgency, and with a coordinated response. ...Our health and economic future depends on how we meet this challenge."

To listen to a podcast about the dangers climate change is posing to Joshua Tree, click here.


This tells us more about the NPCA than about the National Parks or "climate change."

Insofar as climate change is a natural phenomenon, then the parks could not be threatened by it any more than forests could be threatened by lightning-sparked fires, or 'scenic' wildlife was threatened by predatory wildlife 100 years ago. Natural fluctuation in Earth's climate is etched into the stones and recorded in the tree-rings of every nature park. We fall into the same old mistakes when we conclude that the ecosystems we observe now, or measured 75 years ago, are 'right,' and that any alteration is inherently bad.

Insofar as climate change is a human-created phenomenon, which I do not remotely concede, it is a problem that exists on a global scale, and is extremely unresponsive to bleating about joshua trees. If it is human-created, then it goes far beyond the NPS's proper mission, which does not extend to meddling in global economics. Dragging the NPS into climate change politics can only harm the organization's mission in the long run.

As for the Park Service's mission, wasn't there something in the National Park Service Organic Act about the agency's purpose being "to conserve the scenery and the natural and historic objects and the wild life therein..."?

Hmm. Yet the mainstream media continues to ignore fact that we are in a deep solor minimum, the likes of which haven't been seen for a century. According to NASA, deep solar minima were common until relatively recently. The Maunder Minimum, which lasted from 1645 to 1715, is known as the "Little Ice Age". Scientists admit that "no one fully understands the underlying physics of the sunspot cycle". If this is another extended minimum, it seems feasible that we're headed for global cooling and maybe another little ice age. Pray it's not a full-on ice age, which could be potentially more devastating than global warming.

"As Americans, we have faced tremendous environmental challenges before," the NPCA representative testified. "We met these challenges with courage, with urgency, and with a coordinated response. ...Our health and economic future depends on how we meet this challenge."

The NPCA rep has forgotten a most important virtue when intervening on the behalf of mother nature, humility.

Gotta wholeheartedly agree with Anonymous and Frank C!
Follow the money...a whole lotta $$$ going to grants to study this fraud called "global; warming!" Gotta keep them there so-called "scientists" workin'!
I always ask my global warmed liberal say it IS warming STILL...(after all, it's been warmin' since the last ice age except for cooling from 1940 thru the 70')...and we can really turn it when do we stop it from going too far in the COOLING direction? Drive more SUVs? (I actually had one lib blurt out NO! We don't need to do that, it won't affect it! I just said...aha...gotcha! and she got red-faced). LOL
Global cooling will kill us faster than warming ever will!
We are so puny in the dynamics of global climate...we have NOTHING to do with it!! I urge everyone, just as I teach my kids, to spread the word about how much of a farce this is. And how much it's gonna cost us if we go the route of Kyoto and "cap and trade."

The whole global warming issue is so yesterday. It is so Al Gore with a huge dollop of hippy-dippy Earth Day tie-dyed stoner socialist thinking. It is anti-market, anti-freedom and just plain wrong. If the earth is in fact getting a whole lot warmer, which by most accounts it is not, it certainly cannot be scientifically linked to the activity of humans with any degree of validity. No way, no how. Thankfully a large and growing awareness is forming among the vast majority of the world's population that is quite able to understand what a ridiculous hoax the whole thing has been. In fact one of the greatest fables ever foisted upon the consciousness of humankind.

I leave it to Czech President Vaclav Klaus to elaborate:

"Global warming is a false myth and every serious person and scientist says so. It is not fair to refer to the U.N. panel. IPCC is not a scientific institution: it's a political body, a sort of non-government organization of green flavor. It's neither a forum of neutral scientists nor a balanced group of scientists. These people are politicized scientists who arrive there with a one-sided opinion and a one-sided assignment."

When he was asked: “How do you explain that there is no other comparably senior statesman in Europe who would advocate this viewpoint? No one else has such strong opinions...”

He responded: “My opinions about this issue simply are strong. Other top-level politicians do not express their global warming doubts because a whip of political correctness strangles their voice.”

Another interesting question: "Don't you believe that we're ruining our planet?"

His marvelous reply: "Perhaps only Mr. Al Gore may be saying something along these lines: a sane person can't. I don't see any ruining of the planet, I have never seen it, and I don't think that a reasonable and serious person could say such a thing."

I couldn't agree more.

The NPCA is just another Johnny-come-lately spouting off gloom and doom about a subject that makes most rational people smile at the sheer silliness of the concept. We are indeed, as Frank C pointed out, in a historic solar minimum and, as I have said for a quite a few years now, I'll bet anyone that is willing to bet, that the Earth will become much cooler in the next 10 years and NOT warmer.

Any takers out there? Wanna wager some of your carbon offset credits?


Human caused?

The Intergovernmental Panel on Climate Change, which produced the landmark report in 2007 on the state of knowledge on climate change (, is a body that makes decisions by hard-negotiated consensus of the scientists and government policy people from the over 150 member countries -- including the US and China, nations not known in 2007 for their advocacy of climate change. Hence most knowledgeable observers actually regard the IPCC 2007 report as a fairly conservative document, having toned down its findings in order to build the aforementioned consensus of its members. Yet the report stated that "warming of the climate is unequivocal" and "most of the observed increase in globally averaged temperatures since the mid-20th century is very likely [over 90 per cent] due to the observed increase in anthropogenic GHG [greenhouse gas] concentrations."

Beyond the NPS mission?

Kurt rightly calls attention to the Organic Act mandate for the NPS to "conserve unimpaired." In addition, the agency's management policies ( mandate that "NPS managers must always seek ways to avoid, or to minimize to the greatest extent practicable, adverse impacts on park resources and values." [Chapter 1.4.3] The directive for natural resource management is more explicit: the NPS "will maintain as parts of the natural ecosystems of parks all plants and animals native to park ecosystems... by restoring native plant and animal populations in parks when they have been extirpated by past human-caused actions; and minimizing human impacts on native plants, animals, populations, communities, and ecosystems, and the processes that sustain them." [Chapter 4.4.1].

We are not to work in a vacuum: "Activities that take place outside park boundaries and that are not managed by the Service can profoundly affect the Service’s ability to protect natural resources inside the parks. The Service will act to protect natural resources from impacts caused by external activities by working cooperatively with federal, state, and local agencies; tribal authorities; user groups; adjacent landowners; and others to identify and achieve broad natural resource goals. [Chapter 4, introduction]

By calling attention to the ongoing and likely adverse changes in the national parks, neither NPCA nor the NPS is "meddling in global economics" or getting involved in "climate change politics." We're raising awareness of a critically important issue and we've found that the public that cares about the integrity of the national parks cares deeply about this. To make sure we don't get dragged into the politics, parks are generally highlighting our own actions to reduce energy usage and greenhouse gases, hoping that leadership by example is more effective than preaching. I've insisted in my park that rangers be able to back up any statements they make about climate change projections or impacts with peer-reviewed science, which makes them very credible.

Bob Krumenaker
Apostle Islands National Lakeshore

Please get off the global whining hysteria and focus on our parks!

So what? There isn't a damn thing we puny humans can do about it...wake up and smell the sunspots.

Conserving the scenery requires a global carbon cap-and-trade system? The NPS can no more affect global weather patterns than they could roll back the volcanoes of Hawaii. Or should we engage the organization in a crusade to stop continental drift while we're at it?

Climate change is a partisan hot-button, and well outside the NPS's purview. The deeper the NPS gets embroiled in this, the more likely it is to alienate important supporters.

The glaciers at Glacier National Park are not going to vanish in twenty years, the leading researcher reinterpreted his own data and now says they will be gone by 2020: - That is eleven years from now. The same time span as looking back to 1998. No more glaciers in a mountain area means no or at least much less run off in the creeks and streams. And the little water will have a much higher temperature. This is a drastic change for all aquatic ecosystems and and an important one for all the other life forms.

Oh my! The humanity! The glaciers are melting, the glaciers are melting!
Uh...nuthin we can do. The only thing we can do is plug all the vents and fumaroles in Yellowstone, as well as Redoubt, Kilauea, ...well you get the picture.
Get a life, environmentalists!

These comments show why there is so little interest in Climate Change. Too many people believe it's a myth. Media are at fault in this case.. So much data comes from NASA and NOAA that demonstrates climate change. So much has pointed directly to human related causes. And yet this information is not commonly disseminated by the major news media.

It just isn't all that attractive so to do.

Thus, we have comments coming from lack of information.

Global Warming is real. It is human-caused. It can be mitigated, although some of the results may be irreversible, such as the melting of the Greenland ice sheet.

We need an informed public; then we ought to be able to bring about a solution.

Let's put aside the question of whether humans are driving climate change/global warming and approach this issue from another direction.

Here are some givens:

* The Rocky Mountain West is under siege of a mountain pine beetle attack of historic proportions.

* Waters in Yellowstone National Park in recent summers have become so warm that the park suspended fishing in some streams to reduce stress on the fisheries.

* Episodes of coral bleaching, driven in part by warmer waters and aided by disease, are inflicting damage on reefs around the world.

* Sea ice in the Arctic is melting at record levels, and ice sheets in the Antarctic are collapsing at amazing rates.

* Oyster beds in the Chesapeake Bay are a fraction of the size that existed when Capt. John Smith piloted his ship up the bay in 1608, in part due to harvesting, pollution, and diseases enabled by warmer waters.

* Heavy metals and pesticides are polluting the high country of national parks in the West.

* As MRC noted, as glaciers melt away and snowpacks evaporate earlier and earlier, there will be downstream ramifications not only for wildlife, fisheries, and vegetation but also for human communities that depend on runoff. We're not talking merely aesthetic changes.

I use these examples to point out that there is change under way out there across the globe. In the case of those instances that some would say are simply natural cycles, the additional stresses applied by those things that are human-caused (ie, heavy metal and pesticide distributions, higher ozone levels caused by power plant emissions, introduction of non-native species via sea-going ship ballast discharges) exacerbate things.

With that accepted, is it wrong for agencies and individuals alike to strive to lessen their impacts on the environment in whatever manner possible? Or should we simply accept that change is inescapable and let's party like it's 1999?

Kurt, I don't know what more you can do to convince people that global warming is for real. There are some individuals would rather bury their heads in the sand like an ostrich and pretend there's absolutely no global warming crises at all, but just simply a little change in mother natures atmospheric chemistry...and nothing more. It's that same old lackadaisical attitude that gets us into trouble with profound ignorance and old style provincial thinking that coincides with the flat earth society...and that global warming is nothing more then benign subtle change in wind direction. Caveman thinking is still here!

I fear you are right, Anonymous. In some ways it seems to be an immature effort to deny responsibility for what is likely to be a worldwide crisis. We are all culpable. The ostrich-style denial is likely to prevent effective mitigation until it is literally too late. Indeed, we may have already passed the point of no return with rapidly increasing melting of northern permafrost and release of enormous quantities of methane gas.

I want to thank Bob Krumenaker for commenting and speaking out on National Parks Traveler. It's rare for career employees of the NPS to go public, even on issues as important as global warming.

It's astounding to me, given the preponderance of scientific evidence, to see how many are in denial over the fact that our Earth is experiencing an increase in average temperatures at an unprecedented rate. Global warming will do much more than melt glaciers (the evidence of which is more than convincing) and cause sea levals to rise. Rapid shifts in climate will ultimately affect the distribution and abundance of native flora and fauna inside parks and beyond their boundaries. The cause of this warming is not variations in the solar output, as some insist, but the presence of increased levels of greenhouse gases from anthropogenic sources.

The NPS has an important role to play in educating the public about potential threats to park resources. I'm glad Bob has chosen to speak out and weigh in on this topic. Thanks too for the links to authoritative sources of information for more detailed reading.

Owen Hoffman
Oak Ridge, TN 37830

What do you naysayers think happens to the planet when we put so much carbon into the atmosphere? Do you think there is no global climate repsonse?

There is no compelling evidence to correlate CO2 in the atmosphere to rising global temperatures. Ice cores from Antarctica show higher levels of this gas than is found currently in our atmosphere during several ice age epochs, so it is not at all clear what effect it has on the global temperature regime over the broad span of geologic time. In some instances it could cause temperatures to rise and in other scenarios it may not have much effect at all. Climate change is part and parcel of a much larger set of systems than just the singular effect that the emission of carbon dioxide may have in changing the nature of the atmosphere.

My understanding is that ants produce the most CO2 anyway and I don't see us doing anything to upset the dominance or flatulence of the earth's current ruling species.

Our planet is too large and dynamic a place to be able to determine, with any degree of certainty, what drives its climate and atmosphere. The idea that humans have somehow caused the climate to change is certainly the least plausible, to my mind. It is way behind sunspot activity, changes in ocean circulation and temperature or even the position of the continents as they drift around the surface of the globe (which is believed to have caused a mass extinction during the Permian), increased volcanic activity or the massive scale involved in the activities of the insect world.

For more on ants and their rule of our planet:

Ray Bane wrote, "I fear you are right, Anonymous. In some ways it [global warming skepticism] seems to be an immature effort to deny responsibility for what is likely to be a worldwide crisis."

Can we please stop the ad hominem arguments (attacks)? Calling global warming skeptics "immature" and irresponsible in an attempt to discredit an argument certainly would seem to be against NPT's code of conduct.

I do not think it fair to label "immature" or irresponsible Richard Lindzen, a Harvard-trained atmospheric physicist and Alfred P. Sloan Professor of Meteorology at the Massachusetts Institute of Technology. Nor would it be fair to so label the number of other scientists who are also global warming skeptics.

I agree with Beamis that there are far too many variables to make an accurate prediction. Glaciers have been retreating for thousands of years, with a brief pause during the solar minimum that corresponded with the Little Ice Age. Solar output is variable and unpredictable, and scientists do not fully understand the physics behind the sunspot cycle. Milankovitch cycles also play a role in climate change. There's the issue data validity and the heat island effect as well as using models versus empirical forecasts.

Skeptics are not immature or irresponsible nor should the evidence skeptics present or the questions they ask be blithely brushed away. To do so is to act fundamentally; intellectual fundamentalism is a strong disinclination to take seriously the notion that one might be wrong.

I'm willing to admit that I could be wrong. Are you?

Ants, Beamis? Really? I know cows churn out a lot of methane, but didn't know that about ants. Got a link for my edification (seriously)?

Looking back through the comments, usually the Traveler doesn't see this amount of vitriol bubbling up unless the subject is guns in the parks or, (dare I say), mountain bikes in the parks. And somehow this week we've stumbled upon two highly divisive topics -- cellphone towers and global warming/climate change. Who would have figured?

The upside of this is that such interest and debate is one of the key goals here at the Traveler, to get folks thinking and discussing and, yes, even debating. I hope I'm not the only one who's been clicking on some of the links offered in the comments to learn more about the various opinions and thoughts that exist on these topics (although I'll be damned if I can figure out just exactly what a deep solar minimum portends, and it seems some NASA experts are in the same boat). Sometimes such debate and efforts to support arguments is the only way to get some to consider something new.

The downside is that some comments have included unnecessary labels.

Trying to moderate is a tough job. You'll never make everybody happy. We usually try to take a hands-off approach until the very end, but sometimes that's too late. So, please make our jobs a little easier and stick to the high road. There's no shortage of statistics for that.

Ants and termites produce the most greenhouse gases. It's great news for the plant kingdom. We is one big gassy & happy world, we is!

Articles like this bring deniers out of the woodwork, and I don't think it's representative overall. They continue to believe falsehoods and misrepresentations. The idea that the world is too big for us puny humans to impact is a constant that environmentalists always had to deal with. Early on, they said the atmosphere was too big for our air pollution to impact. Same for big rivers and lakes. Now it's the climate.

But getting beyond that, it is important to consider what the NPS' role is for a situation as broad and deep as this. The NPS shouldn't 't take on the role of much larger agencies with an explicit role in policy and/or regulation. But I think that education as to the impact could be it's most important role. Our national parks may be the locale where the most people get the closest to the natural environment. Park bookstores and visitor centers need to rigorously stick to the most well-settled science, even though the kinds of deniers who are responding here will be upset with it.

Ranger talks shouldn't shy from dealing with this issue, even though they will get snide comments from some visitors. Though some readers may have a fit about it, those aspects of the issue where the consensus is strong (see should be well-covered and get the focus.

As well, efforts to help species whose range is being eliminated and where park borders prevent migration could be helped. but not to the degree that we make zoos out of the parks.

I neglected this articles as well, on the current consensus.

I know the Anonymouses are piling up here, but I'm the original, and I think Dean is exactly right. Not right that I'm a denier who believes falsehoods and misrepresentations--anyone who claims that there is such a thing as "settled" science is trying to cover up contradictory evidence through an appeal to authority. There was a time when Newtonian mechanics was the last word in physics...

Rather, Dean is right that we have agencies for environmental policy, and the NPS would gain nothing and lose much by trying to become another EPA. (Or, to get back to the point of Kurt's original post, the NPCA will gain nothing by turning NPS into another EPA.) If there is a role for the NPS in climate change, it is in educating about effects.

1. By talking about effects, we work from empirical evidence, rather than theory. Changes in glaciation, plant and animal distribution, rock geology, air quality--these can all be measured and reported on the local level. Their causes are almost never singular. Let's take an example: wildfire. Increased wildfire rates can be attributed to hotter weather, drier weather, insect infestation, misguided fire suppression policies, and increased human carelessness. In many cases, most or all of these are factors. To global-warming zealots, the main cause is global warming. To the timber industry, you can be sure the main cause is bad forest management. Who is right? In the macro sense, they both are. But to each group, every fire is grist for their respective mills. It is wrong for the NPS, or its representatives, to single out a pet cause and use the parks as a pulpit for policy evangelism. But the evangelists can never see that (I'm looking at you, climate zealots!), because they're right, dammit, and why can't everyone else see that?

2. The parks are discrete areas, with discrete interpretive missions. It is entirely preferable to discuss (for example) receding glaciers in the context of local changes in temperature and precipitation without needing to talk about temperature and precipitation changes on the global scale. We oversimplify the global climate system when we attribute local changes in glaciation to worldwide effects. And we stray far from our appointed topics. If anything, use climate change as a springboard to talk about Glacier NP, but don't use Glacier NP as a springboard to talk about global warming.

3. Ultimately, educating about effects and their potential causes, without taking policy positions (like NPCA's ridiculous and disastrous cap-and-trade system) based on our personal bêtes noire, is good interpretation. These are complex systems. I do not expect any visitor to gain a mastery of climate science by reading a series of wayside signs. I do not want anyone to come to a conclusion about global warming based off my, or any other interpreter's, 20-minute talk about glaciation. What we can do is introduce the idea that these matters are extremely complex, and that they should be skeptical of anyone who tries to sell them a policy proposal based on a 90-second thumbnail sketch of climate science, either for or against.

Forget the ants, they are part of the cycle that is going on for millennia. Co2 in the biosphere is natural and the ecosystems and the global greenhouse is well adopted to it. The problem arises because we pull carbon dioxide from deposits were it was stored for millions of years and sequestered from the biosphere and release it by burning fossil fuels such as coal and oil.

This carbon dioxide is additional to the amount that the biosphere and the meteorological system is adopted to. And only a fool can think that this won't have consequences. It is this easy. Anyone who does not agree is either a fool or has a personal agenda.

Well MRC, temps have been cooling since 1998 when the last warming period seems to have peaked. I won't venture a guess as to why but remain content in the knowledge that the Earth is not static and change is the norm. We roll with the punches but ultimately our fate, as is the fate of all living beings, is extinction. 99% of all species that have ever appeared on this blue and green marble are now consigned to the category of total oblivion. Makes you really admire the clams, sharks and cockroaches for their tenacity.

MRC, If you can't dispute their evidence, call them names. I'm surprised to see you fall into the ad hominem trap. In the interest of civil discourse, ad hominems, appeal to ridicule (calling skeptics "fools"), and other attacks should stop.

As for the "consensus", that's an argumentum ad populum (Latin: "appeal to the people"), which in logic, is a fallacious argument that concludes a proposition to be true because many or all people believe it; it alleges that "If many believe so, it is so." There was once a majority of people who thought the Earth was the center of the universe.

There is plenty of room for debate, and those shutting down the debate--by name calling or other means--are displaying characteristics of intellectual fundamentalism and censorship.

Anonymous wrote, "What we can do is introduce the idea that these matters are extremely complex, and that they should be skeptical of anyone who tries to sell them a policy proposal based on a 90-second thumbnail sketch of climate science, either for or against."

Well said, sir.

I really wanted an answer to my question: What do the naysayers think happens to the planet when we put so much carbon into the atmosphere?

If there is a question as to what happens to all that carbon, perhaps the precautionary principle is the best way to treat the over abundance of carbon created by mans actions. Unless you don't care.

Richard: Check out this link for an answer:

According to Wikipedia, CO2 accounts for 9 to 26% of the "natural greenhouse effect". That's quite a range, indicating uncertainty.

I'm afraid the comments section of National Parks Traveler is, if anything, a less suitable place to get into intricacies of climate dynamics than an NPS visitor center. And it strays far from the original point of the post and the comment thread.

But since you insist on an answer, Richard, I respond that your question is invalid. (This is the correct answer to a lot of life's questions--ask a philosopher!) You seek a simple answer to a question that defies simple answers.

Let's re-phrase the question: You want to know whether an increased proportion of carbon molecules in the atmosphere will cause the planet's aggregate average temperature to A.) Increase, or B.) Decrease. What this question fails to recognize is that there is an unfathomable number of constants and variables affecting that equation. Many, if not most, of those constants and variables are debatable, unknown, or unknowable. Some cannot be measured with any technique we have. Some, we measure entirely wrong. Of some, we are entirely unaware. Some act in completely screwy ways that we don't understand. Many affect each other in real time. Many have effects that don't manifest for years or decades. Most are of infinitesimally small effect.

In concrete terms, those variables include the entire global atmosphere, all liquid, gaseous, and frozen water on Earth, a wide variety of geological factors, every living thing, including rainforests, ants, and humans, the position and mass of the Moon, and any and all solar activity, or lack thereof. We know that the Earth's climate has varied in the past--this is not an insignificant point. So whatever the role of greenhouse gases, we know that some of these other variables can have an impact far larger than anything we have actually observed from CO2.

This is why it is fabulously difficult to solve for the effect of carbon gases on global temperature. And that's assuming that the desired solution is itself a valid [url]concept[/url].

Then there is the matter of feedback loops. All catastrophic climate change predictions depend on the idea that small amounts of warming will themselves cause larger amounts of warming. (This is reflected in Ray Bane's comment, and every claim that it is already, or may soon be, "too late.") This goes beyond the complexity of the original equation, and requires a shocking amount of voodoo and guesswork, to come to a conclusion that is wholly counterintuitive. In the macro view, the physical history of these systems shows that in the most recent few millions of years, the Earth has been fairly steady. An Ice Age here, a great drought there; these things are normal, and do not lead to catastrophic, cascading changes. Yes, massive glaciation across the upper Midwest would be terribly inconvenient, but it's happened before, and life went on. It is the very existence of life, in all its glorious variety, which illustrates that the earth's climate, as a whole, possesses positive dynamic stability.

That is, when something like CO2 concentration gets out of whack, the system as a whole compensates. It's not a conscious thing; rather, the system can exist only because it compensates. Otherwise, it would have spun out of control eons ago, and would never have attained the stability necessary for millions of years of evolution. A simple and familiar illustration of positive dynamic stability would be vegetal processing of CO2. If increased CO2 concentrations (natural or anthropogenic) warmed the Earth's climate, one important result would be an increase in vegetation, as ranges and growing seasons expanded. Greater plant growth would consume more CO2 and sequester it in solid organic matter, leading eventually to a reversion to the mean--less atmospheric CO2, cooler weather, decreased range, less plants. This is merely an example to illustrate the concept, though I stress that this interaction is described by the same great equation that we previously arranged to solve for global average temperature. It has just as many constants and variables, and is just as difficult to test.

Did anyone bother reading all that? Now would be a good time to mention that I gave up on my scientific career goals somewhere around 10th grade, when I figured out that my chemistry teacher was a schmuck, and that I sucked at math. But I was around long enough to learn that science is about debate, not consensus. (Would now be a good time to talk about eugenics, and how nasty things can become when scientists convince politicians that they've figured it all out?) Instead, I'm just a historian. A historian with enough career ambition not to put his name on comments that, I hope, have been reasonable and insightful, but that are contrary to the prevailing political and organizational winds.

Now, here's what I want out of this. I don't want to convince anyone that I know everything, or anything, about climate science. I don't want to convince anyone that global warming is a myth or a hoax; I don't have the scientific moxy to do it. But I do want every reader to stop caricaturing their political opponents! Each camp is made up of a range of people, including some on both sides who contribute nothing more than annoyed scoffs. There are enough evasions and logical fallacies bandied about by both sides to make Aristotle cry. But there are also people who know what they are talking about, and are debating in good faith. Let each reader consider: If you brush these people and their arguments aside, you are no more than a scoffer, and you are not part of the debate--you have picked your team based on the color of their uniforms.

If you want to seriously consider skepticism about climate change, rather than dismissing it summarily because of the color of its uniform, I can certainly recommend starting with Warren Meyer's blog, . He's serious, skeptical, and debates in good faith.

Of course, there are large uncertainties involved in forcasting climate change. Climate change specialists work with uncertain data, alternative mathematical models, competing models, and full quantitative uncertainty analysis. Much of the details are documented in the numerous technical reports of the Intergovernmental Panel on Climate Change (which few who have commented thus far on NPT seem to have taken the time to study).

The overall IPCC conclusion, with 90% certainty, is that the present trends in climate change is being caused by anthorpogenically enhanced levels of greehouse gases.

Here is a link to an extensive 2007 technical summary from the IPCC on the physical science basis for their conclusions that it is highly likely, even when accounting for all known sources of uncertainty in data and models, that the present increases in global warming are anthropogenic (i.e., not from sun spots or from insect gases).

It seems to me that one of the first steps of human-assisted climate change deniers is to lable the IPCC as a "political" rather than a scientific organization. This to me is an easy tactic used to debunk the concern and to argue against the commitment of any societal resources to combat global warming. The global warming deniers recognize that few individuals have the time or patience to digest the scientific literature to independently evaluate the overall merit of the scientific argument. However, when such an independent service is provided by the IPCC, it's simply attacked as being without appropriate credentials.

Now with regards to our national parks, I believe that it is perfectly appropriate for the NPS to become engaged in public awareness education about real and potential threats to park resources and to the park experience. What is delivered in official programs, however, should always have a basis in scientific fact. Public education about the potential impact of global climate change on our parks is a legitimate NPS function. Pubic education about other potential threats is also appropriate.

Whether or not climate change is the single most important threat to our parks depends on one's overall perspective. It depends whether one's outlook extends only to the next park visit, to future visits over the next decade, or whether one is looking at the future of parks over the next 100 to 1000 years. A perspective over the next 10,000 to one million years will likely produce other priorities.

Owen Hoffman
Oak Ridge, TN 37830

"All catastrophic climate change predictions depend on the idea that small amounts of warming will themselves cause larger amounts of warming. This goes beyond the complexity of the original equation, and requires a shocking amount of voodoo and guesswork, to come to a conclusion that is wholly counterintuitive."

Why do you think it requires a shocking amount of voodoo and guesswork? It's actually based on solid science. We have extensive records of climate changes over hundreds of thousands of years. The connection between the ice ages and the Milankovitch cycles (variations in the earth's orbit) are well established and yet those variations aren't remotely large enough to cause climate change of that magnitude on their own. Clearly they triggered something else much more significant.

It was also counterintuitive (to some) once that the earth is not at the center of the universe. Nor do I think it is counterintuitive. It is easy to see that the melting of sea ice, ice caps and glaciers will cause the planet to reflect less heat and absorb more, and that the melting of permafrost leads to more greenhouse emissions.

The evidence that positive feedbacks play a strong role initially after a smaller effect triggers the start of a climate-changing episode is overwhelming. Negative feedbacks are strong, but kick in much later, which is why climate change periods don't lead to ice worlds or a Venus-on-earth.

I think that in the end, the question is this: are people willing to follow the science where it leads, whether or not the result is intuitive to them, or will they always see another conspiracy when they don't like the results of the research.

I once read that one way to visualize the earth's atmosphere is to think of a standard desk model of the earth. The atmosphere would be represented by a single coat of varnish on the globe. The envelop of gasses critical to life on earth is literally tissue paper thin. Now, imagine countless millions of tons of CO2, methane and other human generated greenhouse gasses being released into this amazingly thin layer. Can we impact our climate? The answer seems obvious.

Wow, Frank C. gives me a link to a paper written in 1998, someone else tries to rephrase my question, but changes it entirely. Hey Frank C. Here is a link for you:

Original Anonymous: I did not ask if CO2 changed the climate, I asked what the naysayers thought happened when we raised the CO2 levels.