Category: Science

With an unseasonably cold spring comes a new wave of alarmism regarding global warming, of all things. The science of climate change is rife with political interest on both sides of the issue, so it should be useful to cut through the veneer of “science” (which is often just the ideologically charged opinions of scientists) to the actual facts that are known, and we will arrive at a picture that is quite different from either of the standard views on global warming.

First, we should observe that global climate and weather is a complex, non-linear system with far too many feedback parameters to solve analytically. All models of climate and weather involve probabilistic guesses and estimates of parameters based on past observations in similar conditions. This is why long-range weather forecasting is mathematically impossible, and even short-range forecasts are often wildly inaccurate. Estimating something like “global” climate can be a misleading construct, as the “global climate” is just a mathematical synthesis or average of quite disparate regional climates. A polar climate may become warmer while the climate of a temperate zone becomes cooler. Net global increase or decrease in temperature may or may not affect items of interest such as sea level rise or the greenhouse effect. Geographic distribution of climate is every bit as important as the overall average, arguably more so.

Since climate and weather models depend on previous data in order to estimate parameters, the science of global climate is essentially limited to data from the last half century. Earlier data is not truly global, and anything older than 200 years is almost certainly confined to Eurasia and America. Our estimates of long-scale historical trends are largely based on qualitative European accounts of rivers freezing, malaria outbreaks, and other indications of climate. On the geological scale, we can measure the carbon dioxide content of the ancient atmosphere, and though this is correlated to temperature, it is not the sole determinant of temperature.

Our knowledge of the historical and ancient past provides some apparently conflicting information, which often gets lost in the all-or-none approach to anthropogenic climate change. On the one hand, the carbon dioxide level of our atmosphere is higher than it is been in ages, almost since the time of the dinosaurs. Yet, despite this fact, the current global temperature is not dramatically hotter than that of recorded history; indeed the temperature of Europe was probably warmer during the medieval period. Even in the past century and a half of accelerated industrialization, global temperature has crept up slowly, in fact decreasing in the mid-twentieth century, before increasing only a fraction of a degree Celsius per decade. Indeed, it is debatable whether global temperature has risen so much as a full degree this century, such is the measurement error involved in a global average.

The synthesis of these observations points to a strange conclusion. Although human industrial activity is certainly correlated to a dramatic rise in carbon dioxide levels, this has not sufficed to raise global temperature as much as we might expect. This suggests that, were it not for human activity, we might still be in the “Little Ice Age” that extended from the sixteenth to nineteenth centuries. Global warming, what little there may be, is actually helping to keep the temperature reasonable. This is not necessarily a reason to be blase about future environmental change.

Thre remain serious concerns about ozone depletion and polar cap melting, which in theory could have catastrophic effects. Ozone depletion has already been addressed by a ban on cholofluorocarbons and freon, which are chemically capable of depleting ozone, assuming they actually rise to the ozone layer in sufficient quantities. Polar cap melting is projected to cause a rise in ocean levels by tens of centimeters, not meters, over the next century. This can cause serious crises in some regions, but there will not be any global cataclysm.

Built into the notion of “saving the planet” from some fictional calamity, be it a rogue asteroid or a global tsunami, is the fantasy that man can be his own savior, along with the equally vain belief that man is capable of destroying the planet. Global industrial activities have negligible climactic effects compared to, say, Krakatoa-scale eruptions that can cover a third of the world in darkness and cold. Man is but a caretaker of this planet, not its savior, and if he really wishes to improve the environment, he should try a different approach than the policy-wonking regulation of carbon emissions. Such regulations have only yielded the farce of exchanging carbon credits, and the ridiculously energy-wasteful enterprise of corn-based biofuels, which has driven up the cost of agricultural products in the United States.

Instead of creating a new industry of planet-saving, people should recall their role as caretakers and conservators and learn to consume less, not because they will “save the planet,” but because they ought to make good use of natural goods rather than waste them on frivolities. Yet as long as consumerism and frivolity are considered virtues, environmental do-gooders might as well try to empty the ocean a bucket at a time. Our wastefulness may bring no danger of destroying the planet, but it does threaten our existence as serious human beings.

The most recent mission of the space shuttle Endeavour has drawn attention once again to the fundamental deficiencies of the shuttle program. Although the damage to Endeavor’s tiles was not a threat to the safety of the crew, it served as a reminder of the problematic basic design of having the orbiter mounted alongside its solid rocket boosters and external fuel tank. Whether the debris striking Endeavour shortly after launch was foam or ice, it clearly came from the mounting bracket, and would not have struck the shuttle had it been possible to mount it atop the boosters and tank, as was the case in the Mercury and Apollo programs. The last shuttle missions will fly in 2010, and hopefully the successor vehicle will correct this basic design flaw, returning to the more successful earlier model, rather than banking on the supposed reusability of the orbiter.

In truth, the space shuttle as it exists is not properly reusable, as many of its parts need to be replaced or rebuilt after each mission, and there are extensive safety inspections needed to find fractures or other failures. NASA’s model of tolerating stress failures of individual parts, so long as they do not fracture sufficiently to cause the loss of a vehicle, and replacing them after each mission, was exposed by Richard Feynman in the wake of the Challenger disaster. At the time, there was an alarming propensity among NASA administrators to overstate the safety factor and grossly underestimate the probability of failure, which we now know from experience to be at least 1 in 100, consistent with the prediction of engineers in the 1980s. A culture of secrecy and concern for public relations prevented realistic assessments of risk, and prevented certain facts about the Challenger disaster from reaching the public. NASA prevented state authorities from performing autopsies on the astronauts, and downplayed evidence that the astronauts likely were alive and conscious during their free fall before impacting the ocean’s surface.

Among Feynman’s findings regarding NASA’s attitude toward safety was the irrational practice of regarding a situation (such as certain structural damage) as safe if missions have been successfully flown in that condition, regardless of any probabilistic assessment of failure. This posture resulted in the Columbia disaster, as NASA engineers mistook the success of previous missions as an indication that there was no intrinsic danger to the model of having the shuttle alongside its rocket boosters. Worse still, although the impact of foam against the shuttle tiles was recognized during the mission, the shuttle was authorized for re-entry, denying the possibility that there was a threat to the vehicle.

Now that the dangers of the space shuttle are more fully and publicly understood, it is increasingly cumbersome and expensive to assure mission safety. The space shuttle is also burdened with antiquated electronics and computer technology, so that its reusability has become a liability. A new manned space vehicle needs to be developed, more along the lines of the earlier successful American programs, and the currently successful Russian model.

The development of a new space vehicle, as part of NASA’s new objective of returning to the moon and landing astronauts on Mars, will undoubtedly limit its ability to fund other endeavors. Already, basic scientific research unrelated to manned spaceflight has seen reduced funding by NASA, even though important questions in astrophysics and particle physics can be explored with unmanned vehicles that are much more cost effective. Manned space flight increases the cost of research well over a hundredfold, and it provides no data that unmanned probes cannot provide, save for the effects of space flight on humans. Such a circular justification should not be the basis for an enormous investment. Even if scientific research on humans in space is necessary, this can be achieved on the International Space Station, which is also in danger of losing NASA funding. Considering that NASA advocated destroying Mir in favor of a new station that would not be in exclusively foreign control, it is understandable that European partners strenuously object to its plans to scuttle the ISS as soon as 2016, only six years after completion. The enormous cost and complexity of the ISS make comparisons to the space shuttle program inevitable, and given NASA’s recent track record, it is unclear whether they are institutionally capable of leaner, more efficient design for the moon and Mars programs.