Extinction-level events (ELEs) have a way of gripping the mind. And that’s good, insofar as it’s good to be prepared — panicked and desparate, not so much, but prepared, yes. And these events make for great media, too — news about tsunamis, ozone holes, global warming, radiation disasters and the Mayan calendar are familiar front page fodder.
For the most part, science has been a helpful counterweight to media hype. Where would we be without the science? We know that a sizable comet or asteroid will impact the earth some day, for instance. What do we do with that kind of information, thank you? Become anarchists? Dig a bunker (note: better make it a really deep one). Try to colonize Mars asap? To our credit, our government has developed a workable strategy for saving the earth, beginning with deploying a network of equipment for detecting and monitoring the comets and asteroids that are most likely to strike us some day. This ELE is far from averted, but at least we haven’t let hype rule the day and become paralyzed by fear.
But what happens when we can’t do anything to keep ELEs from happening? Are there any events out there like this? — events that can’t be stopped anyway? Enter the magnetic flip. Geologists have postulated for years now that the earth’s magnetic field may be starting to flip — that north will eventually become south, and south will become north. This event gets mentioned occasionally in reputable news outlets (and more often in less reputable ones), and for the most part, the reputable coverage has been largely balanced and inconclusive, but mostly because we just don’t know what to think — we don’t have enough information.
First though, the disreputable media stuff is complete bunk: a magnetic reversal won’t cause the earth to reverse direction, it won’t cause earthquakes and tsunamis, or the loss of gravity, or the end of all life of as we know it. But in the absence of scientific fact, it’s understandable how we might want to fill the void with speculation.
The fact is that our planet’s magnetic intensity has been slipping over the last few hundred years, which may indicate that a reversal is in progress. According to the geological record, this happens every so often — maybe as frequently as every 250,000 years or so, with the last filp occurring 780,000 years ago. What’s not clear is — well, lots of things: whether this decline we’ve been observing is constant, merely a fluctuation, or the start of an actual flip (or what’s known as an “excursion” — not a flip but just a big decline), whether the earth’s magnetic field will disappear entirely at some point during this transition, how long the flip will take, what the consequences might be for different forms of life on earth, and so on. What we do know is that the earth’s magnetic field has been getting weaker every year at a rate of about 0.07% per year over the last several centuries — meaning a loss of about 10% over the last 150 years. Compared to Roman times, the earth’s magnetic field is about 50% weaker today than it was then.
A magnetic flip wouldn’t necessarily wreak havoc on earth life. It’s the transition period that worries scientists the most. As the field approaches zero before it begins building strength in the opposite direction, what happens then? Will we be exposed to high levels of cosmic radiation and — well — sort of fry? Maybe not. The cosmic ray bombardment could widen holes in the ozone, knock out power grids, and scramble satellite communications systems, but who knows where we’ll be in terms of these technologies in the very distant future. If the flip occurred today, our small electronic devices would be mostly fine (apart from the whole broken satellite and power grid thing) — the effect of the earth’s magnetic field on small devices is fairly minute. But the prolonged lack of protection from increased levels of solar radiation could pose a severe problem for life, unless the earth’s magnetic field doesn’t disappear entirely during this transition but simply becomes weirdly-configured, with a number of different magnetic poles over a period of possibly hundreds of years. In this case, we may not need to worry about protecting life on earth from solar radiation by living underground or relocating populations to areas of our planet where the field strength is sufficient. But we honestly just don’t know the answers yet.
There’s plenty of good news tied to this story. One is that even without any magnetic field, the earth’s atmosphere all by itself provides lots of protection from the sun. As long as we keep our atmosphere healthy (which is definitely not a given), life itself will be protected, at least over a period of generations. Another is that it could take about 1,500 years to reach this nexus (or as long as 4,000 years by some estimates), so we have time to plan. Or, we can roll the dice and bet that as long as humanity is still around by then, we’ll have plenty of other options available to us. But we don’t know if the current rate of decline will continue.
The problem is in what we don’t know. We don’t know what the longer term genetic effects on life might be if the field disappears completely disappears for too long, or for that matter what effect our greatly reduced field is already having on human life. We also don’t what effect this decline may already be having on species who use the magnetic field for migration (birds, salmon, etc.), or whether these species have adapted and will continue to adapt. The geological record doesn’t appear to contain any evidence of mass extinctions that coincide with a field flip.
So what’s a species to do? At our current level of understanding and technology we can’t do anything to stop this event from happening. But we can make ourselves more aware of it. We need to focus on this more, discover more about the underlying science, take more accurate measurements, look for flip evidence on other planets, do more modeling of the flip in labs and supercomputers, model the impacts of this increased radiation on life, and so on — that is, we need to get a better understanding of what we’re dealing with so we can craft a more appropriate and comprehensive policy response than just “it probably won’t be a problem in our lifetime.”
We’re fortunate that with many events like these, even those that aren’t extinction-level, our society has a track record of at least being receptive if not always successful. The hole in our ozone layer isn’t an ELE but our global response has been prompt and admirable. Y2K wasn’t an ELE but businesses and governments everywhere worked to share information and avert what could have been a major disaster.
The same can’t be said about all crises that aren’t quite extinction-level, especially crises with political and economic undertones. Global warming, nuclear weapons in the hands of unstable regimes, the devastation of Africa by HIV/AIDS, and more, are all gripping crises but we aren’t singing from the same hymn book on these, and we may never.
The danger with the magnetic flip issue may be that it’s not sexy. We didn’t unleash it with pollution, science, or politics, it may not end life when it happens, it’s going to happen gradually over thousands of years, and on top of all this, we can’t stop it from happening anyhow, so why worry now (or at all)? The reason runs deeper than just scientific curiosity — it’s good policy. We know it’s coming but we don’t know when, how we’ll respond, what impact another 10% decline in field strength 100 years from now will have on our planet and the life it supports, what impacts the already observed decline may be having on life, what upgrades our current technology will need to survive, and much more. Whether this issue turns out to be a doozy or just a lot of hype is too early to tell. What is certain is that this ELE candidate hasn’t attracted nearly enough scientific and political attention yet, and it should.