Climate Change Explained
Mike Treder
2009-07-11 00:00:00



While generally stable over many millions of years, the climate of the Earth is known to go through periodic and natural "ups and downs" based on a number of factors, some predictable and some not.

For example, our planet's path of rotation around the Sun is not a perfect circle; sometimes we get a little closer and at other times a bit further away. That can result in warmer or cooler eras, often lasting tens of thousands of years. Similarly, the Earth's tilt, which gives us our seasons, is not totally stable; it wobbles periodically, leading to disruptions in climatic stability.



Unpredictable events include things like asteroid or comet strikes that can create global firestorms and subsequent decades-long winters caused by atmospheric ash and haze; supervolcano eruptions can lead to the same kinds of effects, including acid rain and poisoned oceans.

Scientists have been studying these and other factors for a long time and have a pretty good understanding of the major influences that will affect global climate patterns. That's why the vast majority -- a near unanimity -- of informed scientists agree that our present period of warming is not due primarily to natural inputs, but has been caused to a large extent by humanity's altering of the ecosystem.

By examining pockets of air trapped inside glaciers and ice packs, researchers are able to determine, to a precise degree, the composition of Earth's atmosphere at various points over the last several hundred thousand years. They can tell how much carbon dioxide (CO2) was in the atmosphere, a figure usually expressed in parts per million (ppm). This is important, of course, because CO2 is a potent "greenhouse gas" -- higher amounts of this and other such gases in the air cause the Earth to retain more of the heat energy we receive from the Sun. Elevated levels of CO2 lead to a pronounced "hothouse" effect.

Although it is a normal pattern for CO2 concentrations to vary over time, the amount of increase that has occurred over the last 200 years is completely without precedent in human history. Predictable natural surges or declines in CO2 levels are one thing, but what we're witnessing now is at a rate a thousand times faster than would be the case without human input.



Since the beginning of the Industrial Revolution in the late 18th century, mankind has extracted fossil fuels from the ground at an ever accelerating pace and burned coal, oil, and natural gas to generate energy. That process -- which produces greenhouse gases as waste -- has powered tremendous improvements in living conditions for many, but at the cost of a dangerously destabilized environment. Already we have seen average global temperatures rise about 1.3° F (.74° C) over the last 100 years, and if current trends continue, the Earth could heat up an additional 4 to 8° F (2.2 to 4.4° C) by 2100, if not more.

It's essentially beyond doubt, then, that a significant amount of global warming is underway, that it is resulting in noticeable climate change, and that left unchecked this warming will lead to climate chaos with disastrous impacts.

Predictions of melting ice caps, receding glaciers, thawing permafrost, rising sea levels, longer and more frequent droughts, hyper-powerful storm systems, species depletion, refugee migration, disease outbreaks, economic disruption, and other catastrophic results are becoming more plausible with each passing year. Unless something changes very fast, the future does not look very bright.


That's the basics of climate change, and it's nearly all uncontroversial, at least among scientists and analysts who understand the available data. Various interest groups and entrenched industrial powerhouses raise bogus objections and throw out smokescreens to obscure the reality of what's happening, but their phony reasoning is hollow and easy to refute. (NOTE: If you're planning to regurgitate flimsy arguments or cherry-picked stats from denialist groups in the comments, don’t bother because they won’t be approved. We’re here to talk about solutions.)


Proposed solutions fall into three general areas: 1) Rapid, near-total reduction of greenhouse gas emissions; 2) Mass conversion to renewable, carbon-free energy production, whether solar, wind, tidal, geothermal, etc.; and 3) Large-scale projects to directly manipulate the Earth's climate, known collectively as geoengineering. None of these are mutually exclusive, of course, and many experts advocate a combination of all three.

It's unlikely that #1 above will be enacted at a level required to substantially slow the rise in average worldwide temperatures: the political and economic challenges seem overwhelmingly against it. And even if somehow the nations of the Earth could get together to make the necessary commitments, that alone would not stop global warming or prevent climate change, because too many long-term carbon feedback cycles have been triggered already.

Adding #2 to the mix seems more palatable, since it would not be as disruptive to domestic lifestyles and national economies as #1 by itself. Again, however, it will not be easy to implement, and even if great strides can be made, they may not be enough to sufficiently slow the damaging accumulation of atmospheric greenhouse gases. That's why so many scientists and policy makers are now turning to the previously unthinkable possibility of geoengineering.

This is where we enter science fiction territory.



A few decades back, almost no one would have predicted that world leaders would now be giving voice to ideas like injecting millions of tons of sulfates into the atmosphere to artificially darken the skies, or manufacturing billions of flying or floating mirrors to manage the amount of sunlight reaching the Earth. Unfortunately, though, at a time when science and technology are advancing fast enough that techniques once regarded as fiction are nearing reality, our uncertain ability to predict and/or control the full results of these radical undertakings must give us pause. When we're talking seriously about "planet-scale engineering," we should realize that the risk of unintended consequences will be comparably gigantic.

But some futurists, especially those who tout the near-miraculous potential of advanced nanotechnology -- aka molecular manufacturing -- are surprisingly sanguine about the ability of new technologies to "solve" problems like global warming. They confidently predict that soon enough we will have no trouble feeding everyone, that billions of humans will live off-planet in paradisaical artificial habitats, and that Earth can be maintained in a park-like condition.

When I hear such pronouncements, I wonder what political conditions these futurists envision that would allow such immense power to be used so benignly.

I am willing to concede that molecular manufacturing is likely to be the one emerging technology with the power to utterly transform our energy infrastructure, capture and store excess carbon, restore the planet to climate equilibrium, and avert global warming disaster. But what we can't say yet, unfortunately, is how soon that technology will be developed, nor, even more importantly, how it will be used.

Will climate change mitigation be the top priority? Or will a nano-enabled arms race take precedent? Will the leading nations of the world band together to use advanced nanotechnology for the benefit of everyone, or will its emergence result in a mad scramble for superiority, widening inequalities, and decreasing stability?

Technology -- no matter how powerful -- is never a solution in itself. It is only a tool, to be used by its makers for good or for ill. Managing the climate change threat may be the greatest challenge humanity has ever faced. Success will depend far more on us than on our technologies.