It certainly IS true that Earth's climate has seen many great changes, including what we are seeing right now.
However, all indications are, that all of the previous similar fluctuations were due to world-wide calamitous problems. Asteroid strikes, super-volcano explosions, and so on.
In order to declare with certainty that human generated pollution is NOT the current causational factor, they need to come up with another one. And we haven't seen any great asteroid strikes, and we haven't seen any super-volcano explosions. Yet.
So in order to make the “let’s ignore all this because it’s happened before” argument work, they need an alternative cataclysm.
And of course, that still wont deal with the question of what we should do about it, since most Climate Change By Man deniers oppose all actions to deal with it.
Your premise is wrong, OP.
On the other hand, there is a defect in the “the Earth’s climate has always changed” - for one thing, it has never swung *that *fast barring cataclysmic events.
For another, there were no humans then, which perforce limited the impact of climate change on human populations. That has *somewhat *changed since. Whether the current climate change is man-made or not (it is, but for the sake of argument…), the salient point is that if this goes on and no corrective or curbing/anticipatory measures are taken, we’re all of us fucked.
I thought the OP was referring to short-term, quick-acting events, like the cretaceous asteroid boom, not really long-term, slow deals like the ice ages.
The overnight climate changes are often (most often?) due to things like Tambora’s “year without a summer.”
ETA: And what we’re experiencing now is pretty much a short-term, fast-changing event, on the order of decades, not millennia.
No, not true
And, we are actually still in an ice age, we are in one of the in between stages.
So while we humans might in fact warm the planet some, for a geologically short period of time, mother nature still has a deep freeze party planned, that will over ride our tropical beach party.
And she is not having the freezer party due to some calamitous event.
Funny part is i can see humanity screaming for someone to actually induce global warming at that point, kind of ironic i guess.
Asteroid strike, yea calamitous, but not part of any natural cycle, generally a short term event. Possibly not the smoking gun it is purported to be.
They are also a waning event, they become less as time goes by.
Super Volcano? well the specific event is not fun for sure, but it’s simply a byproduct of a natural cycle, so i would have to say not calamitous in the grand scheme of things.
They aren’t one time events and do repeat themselves
The earth goes through a lot of long term things that influence that stuff, change in tilt, change in distance to sun, orbit size/shape fluctuations in sun activity etc.
We may call them calamitous because we fight them, but in the grand scheme of things, no just a normal day in the life of a little blue planet on the edge of the milky way galaxy orbiting a star named Sun, sometimes called Sol or Hellios
Not true. The current warm period of the last 12000 years is caused by natural events. AIUI these natural events are not fully understood, but unnatural and exceptional causes are not suspected, as this is just one in a long sequence of interglacial periods.
There’s never been any disputing the fact that climate change is a natural phenomenon, but that doesn’t mean it’s not influenced by human activity. That’s like acknowledging the obvious human impact on biodiversity and loss of species and shrugging it off by saying “Yah, but species die out naturally, too.” Of course species die naturally. Of course forest fires start naturally. Of course lakes and bodies of water can become toxic naturally. But that doesn’t change the fact that human activity can, and has, accelerated these events with often severe consequences.
Specific effects of climate change are not as well understood. Will climate change result in massive hurricanes every year, or melt all the ice in the poles by century’s end? Who knows? But what is known is that humans are impacting the environment in ways that are measurable, and we know that if current trends hold, the environment that we’ve studied and understood reasonably well will likely change in dramatic ways, and with little time to prepare for the aftermath. Considering the population is growing rapidly and that these consequences could range in mass starvation, dwindling water supplies, and with the resultant effects on pressures on inflation and commerce, perhaps being Pollyannish isn’t the right attitude.
I’m quite willing to accept that the scientists may be right about climate change but I do wonder how some of them can make such authoritative predictions about conditions 50, 100, or 200 years from now when meteorologists can’t even predict the weather for next week with any accuracy. I expect there’s a good answer though.
The usual answer to that is that climate <> weather.
Also, few climate scientists make predictions 50 years out, because no one knows what the world’s civilizations might do to compensate for man-made climate change. We might invest in large-scale carbon sequestration…or we might kowtow to the oil and coal industries and keep on burning. Since that’s an historical determination, not a scientific one, no scientist can make a prediction about it.
(Science can tell you that a large-scale nuclear exchange would be very bad for the environment…but it can’t tell you whether or not one will take place.)
ETA: Also, weather forecasters can tell you what the next week’s weather will be, with remarkable accuracy. Your stereotype is out of date.
I should have been more clear. The relatively RAPID changes we are seeing NOW, have occurred before. THOSE have been found to be due to calamities.
The reason why the term “glacial” has come to refer to change which occurs so slowly that it goes all but unnoticed, because of the VERY long time period involved with what we refer to as Ice Ages.
Those are indeed currently believed to be due entirely to long period, gradual shifts in solar radiation, due to a combination of predictable changes in the relative position of the Earth to the sun.
But they do NOT explain the shorter term changes that the “climate change debate” is about.
We are not, after all, talking about it because we are fine, but can foresee that twenty-six thousand years from now, we will reach the height of another ice age. We are talking about it because of changes which are happening now.
While weather is hard to predict, some scientists that investigate the polar ice are finding ways to make more accurate longer weather predictions. And the reason why is that they do plug in the effects of global warming thanks to CO2 into their calculations.
Short explanation from Polar Weather scientist Judah Cohen:
What would be unnatural is if people somehow kept the earth’s climate from changing. In the time of the dinosaurs, the earth was much warmer. In recent times - except for the past ten thousand years - (we live in an interglacial period) the earth has been much colder. Some scientists think there were times when all the earth was frozen over (the snowball earth hypothesis). There was a time when the Arctic Ocean was a tropical sea.
If people what the earth’s climate to stagnate, that’s fine.
Indeed, one has to notice that cap ice is being lost at alarming rates. And this is while on winter you can get more snow in some regions of the earth. The implication of a warming climate is that precipitation increases in wintertime in shorter amounts of time, and in the summertime the increase in temperature melts the snow and ice faster than before. Leading to more unrest in the weather. It is like when you have slightly warm chocolate with milk and you can see before a more stable system in the cup but as soon as you warm it you can see the milk and chocolate getting turbulent.
This is the key. In the past, on rare occasions like the Paleocene-Eocene Thermal Maximum, the climate has changed relatively fast due to some cataclysmic event. More often, climate change takes hundreds of thousands or millions of years, and the speed of the present man-made changes are dangerous because of the extent to which they destabilize major global climate systems and greatly exceed the ability of the natural ecosystem to adapt. The result will be catastrophically destructive climate events and loss of biodiversity and major risks to food crops, especially in the most vulnerable regions in the third world.
Do you have a cite for this fascinating pile of nonsense? Over the past million years, ice ages have occurred only when absorption of atmospheric CO2 by carbon sinks has reduced atmospheric levels by about 100 ppm from typical interglacial maxima of about 280 ppm down towards the ice age levels of about 180 ppm, a process that takes many tens of thousands of years.
Kindly explain how levels can drop to 180 ppm and an ice age can occur when CO2 is presently soaring to 400 ppm due to industrial emissions of mostly just the last hundred years, a level unprecedented in the million years of geologically modern glaciation cycles. This carbon is coming from fossil fuel deposits releasing carbon that has been sequestered for hundreds of millions of years, carbon that has not been in the atmosphere since dinosaurs roamed the earth.
The answer is that weather is heavily influenced by chaotic factors, climate much less so. I may not be able to tell you with confidence what the weather will be like next week but I can tell you with confidence that it will be warmer in July than it is now. Similarly, it’s possible to compute the indisputable and quantifiable increases in the earth’s energy budget due to increased atmospheric CO2 and other GHGs, whose radiative effects and atmospheric residency times are known. Among the biggest uncertainties in climate projections is not the science but the politics – knowing what our carbon emission profile will be, because it’s so dependent on the politics of mitigation and the success of international agreements.
Nobody is suggesting that it’s “natural” for the earth’s climate to remain the same over hundreds of thousands of years. Nor is anybody suggesting that humans can, or should try to, make that happen.
The point is that it’s not natural for the earth’s climate to change the way it’s changing now on a timescale of decades, at this point in the glacial cycle.
To claim that this short-term, non-cyclic change is “natural” because there have always been large-scale periodic changes in climate is an abuse of science, and isn’t persuasive to anybody familiar with even the most rudimentary facts of climate science.
aldiboronti, if I asked you whether the weather will be colder or warmer two weeks from now than it is today, what would you say? And if I asked you if it’ll be colder or warmer six months from now, what would you say? Why is it easier to answer the latter question than the former, if six months is much more than two weeks?
LinusK, the Earth’s climate does naturally stagnate, by modern standards. Yes, it was warmer in the time of the (large, non-avian) dinosaurs, but that was 65 million years ago. We’re not talking about changes happening over 65 million years, here: We’re talking about changes happening over 150 years, tops.
Weisshund, there will surely eventually be another ice age (though when, I wouldn’t dare to say). But it won’t be a problem. Humans won’t need to do anything about it, because ice ages come on so gradually that we won’t even notice, and we’ll cope by just gradually migrating closer to the equator. The current human-caused climate change is too quick for that to work.
those are 2 pretty good sites that are not wikipedia
Also you could look at the sigmund boyle co2 data
Earth is in an interglacial meaning in between growing big popsicles
The Iceage cycle started about 2.5 million years ago iirc
interglacials typically last 10,000 to 12,000 years, but can in past view last 28,000
Ours has been i think around the 10K range in duration.
The popsicle part of the cycle last something like 90,000 years.
You ask about CO2?
Well if you look at the info they got out of the ice cores (Volstok), i will assume its fairly close since they are scientists and i am not, 325,000 years ago, we have a CO2 rise and spike at 375ppm, an interglacial followed, the Hox something or other, i forget.
Obviously that interglacial ended and the cycle began again, and an amazing thing happened, the CO2 tanked to under 200ppm, and if you look, it did it very very quickly.
It builds slow, it tanks like falling off a cliff, look at all the cycles, look at the 130,000yag cycle
Ok, now Whoosh, present day.
The cycle did not end, not so far as we know of yet, if it had, we would have had a GREENland, and the Antarctic forest, which would probably be nice to see actually, could there be ancient viable seeds?
So, we have no giant cosmic thing jumping up and down screaming ITS OVER ITS OVER!
So we have man, man makes factory, man jams in all the sunk carbon he can find into the furnace, man shoots it into the air.
Man has stopped the ice age cycle, YAY!
Unfortunately no
Man can only get to some of the carbon to free it, he cant get to all of it or most of it.
There is a huge amount of it our little bodies cant even survive to touch it.
He can not get enough of it to effect a change long enough to ride out the cycle the earth is doing, at least not unless he perhaps purposely makes the whole planet inhospitable.
At which point, Earth kills off man, finds it’s balance and continues on with itself.
So anyway he runs out of carbon, Earth continues doing what it does, and it eventually reclaims its carbon, regains a balance, then tanks it. ice comes back continues on, business as usual.
Delayed perhaps, but none the less, it comes back.
It will continue to come back until Earth has finished doing all the things that promote Iceages.
Now when Earth is done doing that, the climate will be something else, what exactly i am not sure, Earth has done a lot of different climate schemes, and i dont know enough to guess what past scheme it might wish to repeat.
And that my friend is not a fascinating pile of nonsense.
I think you’re looking at the difference between those backwards. It is much easier to predict long term trends that individual random events.
Consider rolling a six-sided die. If I asked you to predict a given roll, you would be hard pressed, but if I said I was going to roll it 1000 times and asked you approximately how many did you think would get a 6, you would likely be very close.
If I handed you a slightly loaded die, such that it rolled 6 more often, you still would have a tough time predicting a single roll.
If I handed you a die and didn’t tell you it was loaded, but you rolled it 1000 times, you could use statistical analysis and tell me whether or not the die was loaded.
