The Atlantic has an excellent piece on a drastic climate change event about 230 million years ago, when vast quantities of carbon dioxide gas erupted from undersea volcanoes. We’ve all heard the story of how the dinosaurs disappeared; well, this one is a different story.

But perhaps the most extraordinary aspect of the Carnian Pluvial Episode was not the crisis itself, but the world that came after. Until then, dinosaurs had been a puny and obscure lineage confined to the furthest southern reaches of Pangaea. But by the time the crisis was over, they had spread all over the world—perhaps using the oddly humid pulse to hopscotch across the previously arid wastelands of Pangaea—and rapidly diversified, using the extinction of their competitors to experiment with new lifestyles. The planet would never be the same.

Speaking of climate change, living in the US makes it pretty clear that some of us haven’t yet gotten our head around the whys, the hows, and really, the necessity, of caring about climate change. This is the part that we must keep reminding ourselves: it’s not that climate change destroys the Earth; far from it. The Earth was, is and will be fine. It’s just that the species that inhabit the Earth has and will change with drastic climate change.

If we, humankind, as a species are destined to have the same fate as the dinosaurs, well, so be it. But hey, if there’s one thing us humans have done better than any other species, that’s to change our environment to suit ourselves. Let’s use that to keep Earth’s climate as we like it! A huge chunk of our civilization is based on proximity to water, including oceans; a huge chunk of us are used to certain weather patterns. We won’t like it if either of those factors change. We won’t; the Earth won’t care.

(Hopefully we won’t end up like the dinosaurs. Hopefully, we will (a) keep Earth’s climate under control, and (b) inhabit other planets, at least, by the time the Sun makes Earth uninhabitable.)

Anyway, go read this great article. This kind of story about the paths of life and evolution on Earth is always fascinating to read.

∞

Earth’s climate is changing. If you’re not wearing blinkers, and usually follow the news, this should no longer be a controversial statement to you. (Of course, climate change is a better descriptor than global warming. Earth’s temperatures will not literally rise everywhere all the time. Instead, extremes of climates will become more extreme, and the overall nature of Earth’s climate will shift dramatically.)

For example, from this great New York Times piece:

Especially lately. China is enduring its coldest winter in nearly 30 years. Brazil is in the grip of a dreadful heat spell. Eastern Russia is so freezing — minus 50 degrees Fahrenheit, and counting — that the traffic lights recently stopped working in the city of Yakutsk.

Bush fires are raging across Australia, fueled by a record-shattering heat wave. Pakistan was inundated by unexpected flooding in September. A vicious storm bringing rain, snow and floods just struck the Middle East. And in the United States, scientists confirmed this week what people could have figured out simply by going outside: last year was the hottest since records began.

“Each year we have extreme weather, but it’s unusual to have so many extreme events around the world at once,” said Omar Baddour, chief of the data management applications division at the World Meteorological Organization, in Geneva. “The heat wave in Australia; the flooding in the U.K., and most recently the flooding and extensive snowstorm in the Middle East — it’s already a big year in terms of extreme weather calamity.”

The question, then, apparently shifts to: ‘Is this climate shift man-made? Or at the least, is the climate shift exacerbated by human contribution?’ People who are ‘skeptics’ on this matter hold forth on how Earth’s climate has changed many times before. On the one hand, they doubt claims made by climate scientists—that the Earth is becoming hotter—based on their research, and on the other hand cite the very same scientists’ results on how temperatures on Earth have varied over the millenia.

A crude example—in the New York Times article cited above, a commenter writes:

Hasn’t “extreme weather” raged world wide since time began.? I think the dinosaurs might have something to say about that. It is time to put your words in the proper respective in regards to how long the Earth has existed………Solve our current pressing problems, then worry about how to pay for “climate control”. If you can.

So very true. The question is—where did said climate change, so naturally occuring on Earth over millenia, leave species that existed in those times? Thriving and healthy? Or as dust covered fossils scattered around the world? About 90-99% of all species of life to have existed on Earth are now extinct. Yes, that many.

What many people don’t realize is—it doesn’t matter if the climate shift is man-made. The Earth does not need humankind; we need the Earth to maintain a certain kind of climate for us to thrive, and, indeed, survive. If the Earth’s climate changes to an extreme, and we are not able to adapt to the new conditions quickly enough, we will run a very real risk of joining those 99% of extinct species. The Earth will happily continue to exist, and a new burst of evolution will spring forth a new dominant species to rule the Earth, just like homo sapiens now, and the dinosaurs before us.

Let’s stop fighting over whether we are the reason climate change is accelerating. (Most likely, we are, but as I said, that’s besides the point.) There’s absolutely no doubt human activities at least contribute to global warming (via burning fossil fuels, for example), and there’s no doubt a drastic change in climate is not good at all for the overall health of the human species. We already know what a runaway global warming process leads to: just look at Venus! It’s currently so toxic that we have a hard time even getting our space craft to operate on its surface. We will be extinct long before Earth’s global warming reaches even a percentage point of that of Venus. Not in 10 years, not in 100, not even in 1000, but the seeds of the far future are being planted now.

So let’s do something about it! I can understand the influence exerted by industries that would suffer if we changed our energy usage, but seriously, the health of the human species should take precedence over the relatively shorter term goals and ambitions of interested parties. Let’s stop being tone deaf; let’s take our collective hands off of our ears and eyes and start believing our own data. And please, let’s not selectively trust our scientists. They are experts in their field, and know what they’re talking about.

And no, climate science is not the same as economics and statistics.

The Earth is the only home we have; let’s not burn it down. Even if we are not the primary cause of the fire, we have to make our best effort to contain it, and if possible, put it out. Our survival depends on it.

P.S.: While looking for a suitable link for global warming on Venus, I found more links disputing the comparison than affirming it. Interestingly, most of such articles, with analyses, are written by, for example, Economists, and medical doctors; articles by climate scientists seem to be curiously missing. I will address this “dispute”, since I brought up the comparison with Venus, but in a separate post—let’s only focus on Earth for now.

As is well known, Earth plays host to numerous meteors, some of which are big enough to reach the Earth’s surface as meteorites. What scares us, the human species as a whole, of course, are the ones large enough to cause significant damage—especially the ones that can cause mass extinctions.

Are the rates at which meteorites arrive at Earth cyclic? Can we predict when the next mass extinction (meaning almost certainly the end of the human race as we know it) will be upon us? It’s all in the statistics!

Of course, there’s no other way make predictions, other than to watch for patterns and extrapolate the timescales involved into the future. Based on past records, there are certain hypotheses about when and why some big rocks hurl towards the Earth—and the most interesting of them involves a phantom solar companion. Christened “Nemesis”, this hypothetical star is supposed to be lurking at the outer edges of the solar system, and like a classical villain hurling chunks of rock from the [Oort Cloud][linkoort] into the inner solar system. Essentially, he’s made out to be playing Duck Hunt, with Earth as the Duck, of course.

But all of this story (and other cyclical hypotheses) depends on a robust analysis of data, which involves robust statistical methods. Everything is a question of probability, of course—you can’t get absolute numbers in situations like these—and it’s no easy matter to set limits to what the error tolerances are. To understand how difficult the whole process is, consider the data in this case: cataloguing previous impact craters on Earth against how old they are. There are numerous craters, of course, but there are also erosion processes that make life difficult.

Well, according to this article by Ian O’Neill, there isn’t much statistical evidence after all for Mr. Nemesis. Researchers at the Max Plank Institute of Astronomy turned to Bayesian probabilities to look at the data, and concluded that there isn’t periodicity in the data as previously thought. Bayesian probabilities are a little more complex implementation of probability theory, where the question asked is: “What is the probability of event A, given that event B precedes it?” Event B, of course, has its own probability of occurring. (There are other complexities, of course, but that’s the simplest case.)

We’re not doomed by Nemesis after all! Apparently robust statistics has saved the day once again. :)

Or has it? The scientists did not find cyclical evidence that would point to Nemesis, but they think they’ve found evidence for an increasing rate of meteorites over the past 250 million years. And before you say “erosion!”–which would decrease the number of older craters—apparently the same trend is observed on the Moon, where there is, of course, no erosion going on.

So—we’re not out the woods yet! ;)

(In case you’re seriously wondering—no, there isn’t a serious chance that we’d be hit by a big one soon. There isn’t even a less serious chance. Doesn’t mean it’s impossible, though!)