So, as of last year, the mean concentration of carbon dioxide in our atmosphere was about 389-390 PPM (parts per million)
, which - for those spread sheeting at home - is actually a slightly higher concentration than the IPCC's A1B model was expecting we'd reach by now.
The what model?
The IPCC (Intergovernmental Panel on Climate Change) - the body of scientists that are, in essence, working in a Manhatten Project-esque routine, albeit with significantly less risk of criticality incidents, to understand human impact on the climate - computed 6 different models for the future of Earth's atmosphere & temperature, based on a variety of factors: The A1B, A1Fl, A1T, A2, B1 and B2 models.
The models are visualized in these graphs:
And the IPCC itself, of course, has a very readable (in my opinion, anyway) breakdown of their modelling procedures & analysis right here
I can't read all of that right now! I'm on my lunch break!
Well, the A1B model is, in essence, the 'benchmark' model. It assumes that the current output of CO2 emissions will remain steady, and methane release as a result of thawing marshland in the northern latitudes will not steadily track upward with a rise in temperature (it assumes a peak point for methane concentration at about 2,500 parts per billion around 2050, with a drop-off thereafter). It's the 'we do nothing, but nothing else goes wrong either' model, and results in what's colloquially known as a '4 degrees Celsius world' by the end of the century (a world where the mean global temperature is 4 degrees greater than it was in the 1900s, before heavy industrialization).
The model the global community should be most interested in aiming for is the IPCC's B1 model (or better), which means we need to aim to have a [i[peak[/i] CO2 concentration of about 450-475 parts per million by the year 2050, and have that figure either hold steady or (preferably) decline going forward, in which case we'll 'only' be faced with what's colloquially known as a '2 degrees Celsius world' by the end of the century (a world where the mean global temperature is 2 degrees greater than it was in the 1900s).
We need to significantly reduce our emissions - and, to be honest, probably employ some sort of artificial mitigation technologies - in order to hit that target. Right now, we're shooting for about 550-600 parts per million by 2050.
4 degrees? 2 degrees? Those numbers are small. I am not concerned.
This is what a 4 degrees C Earth is projected to look like.
The exact range of extinctions is hard to predict, but 40% of known species is on the low end of the models, 70% on the high end. Most significant extinctions would be of marine life, with much of the ocean becoming, effectively, a liquid desert thanks to coral bleaching & plankton extermination. Depending on the extent of plankton death & the frequency of forest fires (which are expected to dramatically spike, partly due to temperature changes & rainfall pattern alterations, partly due to pest surges as insect predators are depopulated), the Earth's atmosphere might very plausibly become so oxygen depleted that large mammals - like homo sapiens, for example - cannot tolerate the conditions.
Of course, that's a worst-case scenario; it might 'only' be that Earth becomes a scorching Hell-hole with extremely limited water sources that every state tears itself apart trying to seize control of, as rainfall patterns have changed, established aquifers have begun to dry-up and new aquifers have yet to be created.
If a 4 degrees C world represents the outer margins of what conditions humans may be able to survive, a 2 degrees C world is 'merely' horrific. About 20-40% known species extinction (again, mostly marine life). Water sources would be substantially stressed, especially in the developing world, and the western world could expect an unprecedented immigration crisis. At the end of the day, though, we would very likely pull through it.
Wait, what!? People have been saying this is no big deal! I have been buying green products! I'm carbon neutral! Al Gore played that upbeat song at the end of Inconvenient Truth and said it was all happiness and ponies and lime Jello ahead!
Unfortunately, we haven't been hitting our emissions targets. In fact, we're not even on track to trend with the A1B model (the really bad model - though, certainly not the worst of the models. Some of them predict that if we do not curb our emissions by 2050, we'll set-off a positive feedback reaction involving methane and, eventually, water vapour that will turn the whole planet into a desert).
What we started doing back in the 70s through to the early 90s was too slow, and on much too small a scale. And it continues to be, to this day. We're going to need to make some very tough choices about energy industries that currently keep the food on the tables of a lot of blue collar, low-income people in the west; oil & gas companies and coal companies will boast about how they have become necessary parasites that keep whole communities solvent, and they're fundamentally correct in most cases.
Well we sure can't just pull the plug on coal or oil & gas, that's crazy! My whole extended family works for Halliburton!
As a consequence of not making much smaller & less traumatic adjustments in the past, we're now faced with grisly choices. Pretty soon (well, 'pretty soon' on a geological timescale; from our perspective, it might seem like there is a lot of time still. As they say, though, years wheel by) we'll be unable to make any meaningful choices (or rather, stuck with the 'choice' of inaction). We can sacrifice now (or, to put it in a less sugar-coated way, force other people to make sacrifices now), or we can shove the burden back a few more decades and force the grandchildren of the current generation to bear witness to the whole human enterprise unravelling around them (you might even have to watch it yourself, as a far less able-bodied senior citizen. 90 years is within a human lifespan, these days).
We have to start taking very clear and very strong stances on how much CO2 can be put into the atmosphere, if we'd like to think of ourselves as moral or forward-thinking in any interesting way, even if that means a lot of people lose their jobs and a few companies can't operate above the red ink.
I will not / cannot lobby for people losing their jobs even if that means the Earth will be atomized next Thursday. Isn't there anything else I can do?
If you're already carbon neutral, probably not.
If you're not already carbon neutral:
- Replace your home's lightbulbs with florescent bulbs or, better yet, LED bulbs. Yes, they are expensive (mostly because standard bulb are just a glass dome over a piece of tungsten wire. Not much to it); they'll also last longer and cost less to operate. Just buy the fucking things.
- Look into solar panel installation. It's out of most people's price range, but you might be surprised at what local manufacturers can do for you deal-wise.
- Try to be more vigilant about recycling & waste reduction. I was personally surprised at how easy it became once I got into a routine of not just stuffing every single thing into a garbage when I was done with it.
- Use public transit if it's available. Look into either buying an electric car when you need to replace your current automobile, or converting your current vehicle into an electric one. If none of that is remotely possible, make sure you maximize your vehicle trips; car-pool, don't take the vehicle out on errands every single day, etc.
- Do not waste your money on 'organic food'. Most of the time it isn't locally grown anyway, and it does not in reality actually reduce emissions. Farmers are still going to sew & harvest their crops to sell, even if demand did decline (which it won't anyway).
- In general, just try to be conscious about how much energy you spend, where the energy is coming from & whether or not there's a way to accomplish what you're doing by using less energy and / or taking the energy from a source that will not directly generate CO2.
Hey now, I just heard my local TV weatherman say that this whole thing is a hoax! You just want me to buy green products that you're invested in, and then you're going to create a Marxist dystopia with windmills and bio-fuel Esso stations where the only thing to eat is hemp-flavored ice cream!
First, I don't give a shit if you never buy a single 'green' product in your life (...well, except for fluorescent or LED bulbs. It's the Goddamn 21st century. Buy Goddamn 21st century lighting technology, you fucking Luddite). The average population in the west being carbon neutral is not nearly enough (but it does show that you're at least willing to lead by example).
Second, all of the world's major science bodies agree that climate change is real, agree that we are causing it, and agree that negative consequences are on the horizon
. The only people who think climate change as a whole is a hoax are hopelessly ignorant ideologues, and most people who claim
it's a hoax are fraudsters. Only a fringe handful of academics still clings to the belief that global warming isn't being caused by human activity (Richard Lindzen is the most well known; his papers detailing his 'Infrared Iris' hypothesis are, in my opinion, pseudo-scientific junk, and it's a pity that the academic community has been so polite about the issue. Gee whiz, awfully convenient that the very flagrantly flawed data collecting method employed by Lidzen who's results then couldn't be replicated by anyone turned-out out to be a 'mistake' that happened to coincide with his political ideology. He really should've been hung out to dry on that matter, and I don't care what Harvard's faculty thinks of him or how many previous papers he's written).
At this point, given all of the information we've collected, the appropriate reaction to anyone claiming that global warming 'isn't real' is to regard them as you would a Young Earth Creationist.
So, there you go. Global Warming.