Cool visualization.<p>It's worth keeping in mind that the modeled data lines up with reality because it's supposed to. That's how you calibrate your model, by making sure it fits reality.<p>The real trick is to see how well your model extrapolates from the data you have out into the future. As in, if you feed it data up to, say, 1990, will it correctly spit out 2015 temperatures that fit the reality of 2015, or will it spit out crazy 2015 predictions like the models that were built in 1990 did. And, the bigger question: How will its predictions for 2040 (given 2015 data) match up to the reality over the next 25 years.<p>We seem to be getting a lot better at the modeling side. That's a good thing, since the first couple decades of watching people panicking and fighting each other over whatever scary results came out of the first generation climate models wasn't any fun to watch.
This repeats some buried comments but I think it's worthwhile: I'm not a climate scientist, but in my experience the absolute most reliable, most time-efficient way to learn about climate change is the IPCC reports. I wonder if there is anything written in any other field that compares:<p><a href="http://www.ipcc.ch/" rel="nofollow">http://www.ipcc.ch/</a><p>Specifically, if you are short on time, read the 'Summaries for Policymakers', written at the level and attention spans of non-technical politicians. They are quite readable and as I wrote in another post, if they can understand it, so can you. :) (The longer reports are fascinating, if you have an interest in science and want to get lost in something.)<p>As I understand it the reports are prepared by a global team of hundreds of scientists, and reviewed by thousands more.[1] (Seriously, has anything like that existed in any other field?) They are meant to cover the breath of climate science and the reports also are meticulous about the language of probabilities.<p>Spend a little time reading them and it will save you the time of reading 99% of what's written elsewhere, and you'll be much better informed.<p>---<p>EDIT:<p>[1] Review process: <a href="http://www.ipcc.ch/activities/activities.shtml" rel="nofollow">http://www.ipcc.ch/activities/activities.shtml</a> (scroll down to "The AR5 Writing and Review Process") -- for example, one report had over 50,000 comments on two drafts from >600 experts.<p>---<p>EDIT 2: Website interface help.<p>Can you believe this needs to be written, and for HN readers? I had JavaScript off which makes the site usable (if not pretty). With JavaScript on, apparantly the UX concept is 'Easter eggs':<p>There are 4 images arranged horizontally at the top; these are report covers (with text too small to read even if you knew they were clickable). If you click a report cover then the section beneath it changes to display a description of and links to that report.<p>All that work making the reports accessible to the world, hamstrung by web design.
Helpful when reading this thread to keep in mind Michael Mann's six stages of climate change denial:<p>1. CO2 is not actually increasing.<p>2. Even if it is, the increase has no impact on the climate since there is no convincing evidence of warming.<p>3. Even if there is warming, it is due to natural causes.<p>4. Even if the warming cannot be explained by natural causes, the human impact is small, and the impact of continued greenhouse gas emissions will be minor.<p>5. Even if the current and future projected human effects on Earth's climate are not negligible, the changes are generally going to be good for us.<p>6. Whether or not the changes are going to be good for us, humans are very adept at adapting to changes; besides, it’s too late to do anything about it, and/or a technological fix is bound to come along when we really need it.
Please don't take this as a denial of climate change, it is an honest question. How do scientists learn the levels of ozone, aerosols, green house gases, and the other data points going so far back at a global scale? Is the data from before the latter half of the 20th century spotty? If so, why is it considered good enough to use in a context of scientific research where quality and correctness of data is paramount?
The chart at <a href="http://d1vn86fw4xmcz1.cloudfront.net/content/royptb/363/1501/2299/F11.large.jpg" rel="nofollow">http://d1vn86fw4xmcz1.cloudfront.net/content/royptb/363/1501...</a> (put together by The Royal Society) shows that <i>most</i> deforestation in Eastern Canada occurred over 400 years ago. This one <a href="http://mongabay-images.s3.amazonaws.com/12/1203all-time-deforestation.jpg" rel="nofollow">http://mongabay-images.s3.amazonaws.com/12/1203all-time-defo...</a> shows a shift starting about 300 years ago from temperate forest removal to tropical forest removal. Together, they start to paint a picture of massive deforestation, hundreds of years ago.<p>It's important to note that history didn't begin in 1880, and that some effects lag their cause. Forests, along with oceanic flora, normally sequester Carbon from CO2 and return O2 to the atmosphere. However, this effect only takes place when the forests are actually there.<p>I don't have any religion, one way or another, about climate change and its causes, but I think we won't learn anything from media propaganda like this. It doesn't even bring up the possibility of albedo playing a role in climate change?
Does it bother anyone else that only the Global temperate has its axis labelled?<p>What is the orbital wobble measuring?
What is the volcano line measuring?
Is that decreased forests or decreased land use?
Should be be using more aerosols?
Is that meant to be suns temperature or sun activity, or sun colour?<p>I realise that the actual data is from reliable carefully measured models but it makes this illustration so pointless.
In climate 130 years is not a long time. I wish these articles showed graphs with historical data that go back thousands of years so that I could see how, in a historical context, greenhouse emissions are affecting the world. I've only ever seen data from the 1900's, and it looks pretty hockey stick, but would be interesting to see fluctuations with the ice age(s) and local highs included.<p>Edit: historical data is of course not available, but approximations must exist?
This graphic really just plays into the hands of climate change deniers. No labelled axis, a timeline of only 100 years (you could also argue the dinosaurs caused global warming), and the quite proud declaration at the end the argument is really "no contest" under the assumption that correlation == causation. I could also make a graph that shows the increase in global temperature correlating with the rise in the Latino population, could I then declare it a "no contest"?
This article only serves to stroke the ego of people who already believe that CO2 emissions cause global warming. It does nothing for people who already deny it.<p>Evidence, no matter how strong doesn't serve to change the nature of a man. People would rather bend the logic and the evidence to fit their convenient perception of reality.<p>Which brings me to the question: "What can change a nature of a man?" Imminent danger? If an assailant had a gun pointed at your head, it'd be impossible to deny. How can this evidence about global warming be presented so that it can't be denied?
Not trying to argue against manmade climate change here, but the conclusion is inconsistent with the stated point/headline.<p>The main question is whether or not humans are the primary driving factor in the changes observed. Graphs show lack of correlation with various manmade causes and some natural causes, but then the conclusion is reached with the graph of "the influence of greenhouse gas emissions." In other words, the "nail in the coffin" evidence is simply showing the <i>effects</i> of the problem graphed against the problem itself; it doesn't prove one way or another whether the <i>cause</i> of the rise in greenhouse gasses is manmade.<p>Downvote as you will, but that doesn't seem like science to me; it feels like proving a point by simply restating the point.
Since I seem to be repeating myself all over this thread:<p>It is basic physics (the optics of IR and visible light and thermodynamics) that trace amounts of CO2 and methane can significantly warm the atmosphere.<p>We know physics pretty damn well, and if you do not accept this, there is no conversation.<p>Sure, one should look at the data to see to what extent this is happening and there are all kinds of questions one can ask. But all this talk of "correlation is not causation" is nonsense.
> "No, it really is greenhouse gasses." .. "See for yourself."<p>Being patronising has such a great track record in turning hearts and minds, I'm glad they didn't stoop to such decadent clap track as "engaging with opposing arguments".
What's always been puzzling me is why the relationship between man-produced emissions and climate is considered important in the fossil fuel debate.<p>As if it's not enough that the air in major cities and vast parts of entire countries is literally toxic.
Well correlation is not causation.<p>is it y=f(x) or y=x(f)? aka is is warmer because of the higher greenhouse gases or is there more greenhouse gases because of the warmer climate (that could have been caused by things like leaving an ice age and approaching a warm period in Earth's life)<p>Just to clarify, i support green technology and I think this is definitely the way to go but I don't like the unjustified crusade using proofs that can be ripped apart in minutes.
It's really depression to see such a large aggregation of smart people applying their abilities to nitpicking details of global warming instead of coming up with solutions.
Very cool visualization and great way to display it.<p>As someone who refuses to trust authority and wants to understand things for myself before making a decision, global warming is very frustrating because nobody will answer my questions without personal attacks or appeals to authority. I don't have an agenda either way, I just have a very inquisitive mind. Have any of you felt the same?<p>Some of the questions I have that never seem to get an adequate answer:<p>1) How are the models validated? Is it like backtesting a trading strategy? Come up with a hypothesis that seems to fit historical data, then let it run with actual data, and see how accurate it is? If so, how have the models held up?<p>2) How do they account for confounding factors and how do they separate causal correlations from mere correlations?<p>For example, at 95% of fires firemen were present. Firemen and fires are strongly correlated. But nobody would say firemen are the cause of fires.<p>Cholesterol was thought to be a causal factor for heart problems because it is strongly correlated but they later found it is not a causal factor. Something else causes the heart disease and cholesterol raises when heart disease is present. They can use it as a predictor of heart disease but it is now understood that cholesterol doesn't actually cause the problem.<p>3) It seems to me that for a model to be trusted it must have predictive capability, and it must fit a physical model of our current understanding. How do the various models hold up with these criteria? It seems like climate is still a very complex field that we don't fully understand.
My only problem is that the planet is over 4 billion years old and as this shows, we've been collecting climate data for a little over 100 years. The natural skeptic in me isn't ok with establishing a trend based on 1/40,000,000 of the available data, the sample size is simply too small. Am I completely off-base with this?
Reading (audio book) Nate Silver's book on prediction, he looks at the predictions made by James Hansen in 1988 and IPCC a few years later.<p>He says the predictions were generally pretty good, maybe IPCC was a bit on the high side compared to what happened.
It's impressive to see the size of the spikes that volcanic activity causes in this graph, as an event that has no correlation with human activity.
After reading these comments, it is clear that the ones who have their mind made up and are not open to debate are the warmists. The fact that merely asking questions incites such aggression suggests only one thing. They just don't know and are scared to admit it to themselves. This is the exact same behavior seen among religious cultists. They have not read all the evidence or most of it themselves, but follow the high priests unquestioningly because 1) It makes them feel better and morally superior and 2) The burden of proof is not on them. They can always evade and say "all the experts/high priests agree" or "read the IPCC" etc
Agreeing on the provenance of the warming seems to be a red herring when we urgently need to figure out how climate change affects us. Which areas will be flooded, which areas will become inhabitable, will we be able to grow more food or less, how many more people can we expect to starve, how many jobs will be created and lost, how will it affect life expectancy? I realize such research is going on -- I'd like it to be promoted better. The world is already an inhospitable place for many people and we already don't respond well enough. Currently I don't see why we would respond any better if things get worse.
From all the credible data I've
been able to find, the
main global warming
is just from the coolest
times of The Little Ice Age.<p>For the past 100 years, I see
little credible evidence of any
significant warming, and what
there is may just be that we are
still pulling out of The Little
Ice Age, e.g., slowly warming the
oceans from the cooling they got
in The Little Ice Age.<p>The best data I found is in<p>Committee on Surface Temperature
Reconstructions for the Last 2,000 Years,
National Research Council, <i>Surface
Temperature Reconstructions for the Last
2,000 Years</i>, ISBN 0-309-66264-8, 196
pages, National Academies Press, 2006,<p>available at<p><a href="http://www.nap.edu/catalog/11676.html" rel="nofollow">http://www.nap.edu/catalog/11676.html</a><p>There as I read the graphs, as of 2006,
the temperature was essentially the
same as in the year 1000,
and the increase in temperature
over the past 100 years was much
like that from year 900 to year
1000.<p>For the climate model predictions,
all the data I've seen have
the predictions very significantly
different and all significantly
higher than the actual temperatures.<p>For the title here "What's Really
Warming the World?",
from all I can tell from credible
sources, so far, to any
significant extent, nothing.
CO2 is not strictly human emissions and to imply so is so dishonest is ridiculous. of course any gross simplification of the environment as done in this presentation is explicitly to deliver a message decided before the numbers were assembled.<p>the primary co2 process is ocean to atmosphere exchange, the earth to atmosphere, and then to mammals respiratory activity. So then you get down to how much CO2 is man pumping into the atmosphere beyond that point and which sources are direct versus indirect.<p>finally since their numbers only are observable to 1880, how accurate can we assume them to be? If were are extrapolating we could do it further back than 1880 to periods where man was present in significant numbers and thew world was warmer<p>There is climate change, never has been a period of time where it hasn't, but junk presentations are just that. Take numbers out of context, put in easily to dismiss arguments along side, and it appears to make your point beyond reproach (its like say, the sky is blue and you agree, don't you? the going off to explain why something indirectly related is bad or good)
Deforestation? They reject this because we replace forest with light reflecting materials which they claim causes slight cooling. Last time I checked, it's way cooler in a forest than standing in a parking lot. Nature uses the energy from sunlight to create biomass. Anything else either reflects it or turns it to heat.
I don't deny man made climate change, but this argument seems to be weak. Just because two factors go up at the same time doesn't mean one caused the other. See <a href="http://www.tylervigen.com/spurious-correlations" rel="nofollow">http://www.tylervigen.com/spurious-correlations</a>. It is necessary but not sufficient to show that greenhouse gases went up in concert with global temperatures.<p>Not that one expects them to lay our a sweeping, thorough case for man made climate change in such an article, which would be an unfair expectation. It seems more like a showcase for the bit of javascript razzle dazzle than anything else, as other commenters pointed out, surely no one involved with this article expected it to change anyone's mind one way or the other.
Notably absent is con-trails. The jury is still out, but there is strong evidence that they can have a significant effect. The rise of jet travel has also coincided with hydrocarbon use. Water vapor is also a much stronger greenhouse gas than CO2.
The deforestation graph only seems to account for the difference in emissivity between forest and grassland.<p>Surely the CO2 absorption and the effects of forestation on cloud cover would have a non-negligible effect.
There are three things that bother me about climate science.<p>1. Certainly in years past, anyone who even dared question that global warming wasn't real or wasn't man made was lambasted. That's not science. That's religion. Even just asking questions gets you labelled a denier. These, to me, have been and are reasonable questions to ask:<p>- On what basis are we saying the earth is warming? Datasets for the last 1-2 centuries are still pretty narrow compared to how old the earth is and how hot and cold it has been at various points;<p>- Is that warming, if proven, man-made? It's reasonable to investigate other possible factors that may well add to the effect caused by man;<p>- Can we even do anything about it if it is? How expensive will it be?<p>- What, if any, are the good effects of climate change? It can't be all bad but it just bothers me when I see things talking about how it will hurt, say, North America. But will it makes other parts of the world, currently largely uninhabitable, more hospitable?<p>I'm actually genuinely curious about these and other questions and it bothers me that even asking them is a problem.<p>2. The lack of transparency. This goes beyond climate science actually but any published thesis or study on the subject should make data sets publicly available and--this one is really important--make any code for any computer models open source. Transparency and reproducibility are at the heart of scientific method are they not?<p>There have been incidents (eg climategate) where no scientific misconduct was found but the text of certain emails really leaves a bad taste in my mouth because it reads very much like "here's the conclusion, now let's prove it".<p>3. The history of climate predictions has been pretty terrible and each time we're told "no trust us, this time it's totally different".<p>It's not that I don't believe in man-made climate change. I actually think whether or not it's true it's probably largely irrelevant. There are simply too many of us and we're running out of too many things in the coming centuries that this will be corrected one way or another in such a way that climate change--true or not--will be the least of our problems.<p>One of the interesting and depressing explanations for the Fermi Paradox is that the sphere of influence of life is ultimately capped by the speed of light, which is geometric, and life expands exponentially. Life always catches up eventually.<p>You see this in nature where algae blooms for example will explode in rivers killing all other life until they themselves can't survive and they all die. In more balanced ecosystems there are other factors to keep any one species in check. It really seems like nothing is keeping up in check now so are we just another algae bloom?
What about agricultural water output?? Inverse of the deforestation curve already shown is also potentially convincing.<p>If you want to go spurious, you could also run a correlation between wind power generation.
The documentary Merchants of Doubt (2014) provides a great look into paid shills on US media. They aim for confusion and they've been doing this kind of work for a long time.
By no means suggesting CO2 isn't responsible for global warming - quite frankly I have zero idea, I just try listen to what the experts say. However, this article in particular is pretty offensively stupid. It shows some graphs that indicate a correlation between CO2 and heat increase. That's by no means scientific evidence for a <i>cause</i>. Again, not saying there isn't any evidence CO2 is the cause, it's just this article is incredibly misleading.
So what they are saying is that we should be pumping large amounts of Aerosols into the atmosphere?<p>I think we need less confirmations that there is a problem and more solutions to the problem.
I am not a scientist but I've always had a sneaking suspicion that blacktop converting light from the sun into heat had something to do with it. I'd actually LOVE to hear what a scientist thought of this hypothesis.<p>I also wonder if all the coal we material we burned for heat (coal and such) didn't have a cooling effect - particularly in the cities where a lot of the accurate temperature measures were taken. Again, not a scientist - truly curiously.
GHG seems to match Temperature quite well. But GHG is cut-off at the year 2000. I wonder if the closeness of the fit continues?<p>Also, what's up with the error bars around GHG's? Is there really that much uncertainty surrounding CO2 concentration in the atmosphere? I thought readings were accurate to ~1ppm where the trend is currently +3ppm/year so why are the observations (in the modern sensor era) uuncertain by about ~45ppm?
I am not negating the global warming issue here, but what I see is just a correlation of two time series, much like the correlation between "US Spending on science, space and technology" and "Suicides by hanging, strangulation or suffocation" [1]<p>[1] <a href="http://www.tylervigen.com/spurious-correlations" rel="nofollow">http://www.tylervigen.com/spurious-correlations</a>
It would be helpful to know more specifically what the final green line is actually representing; 'shows the influence of greenhouse gases' is a pretty major divergence from the specific quantitative measurements used in every other line.
Note that these graphs explain the factors of the simulation model, and is not comparing data to data.<p>From the FAQ:<p>"The colored temperature lines are the modeled estimates that each climate factor contributes to the overall temperature."
Unrelated, but this part amused me in that it was probably intended to be an argument <i>for</i> the quality of the model:<p>>ModelE2 contains something on the order of 500,000 lines of code, ...
I'm just so utterly amazed that they could measure temperature with such precision for so many years. I'd imagine rooms full of temperature calculator people crunching numbers from their precise temperature measuring instruments. Bravo!
At this point, any rational person understands the problem. Ok. We get it.<p>So how do we fix it? It seems like everyone is focusing on proving that it is caused by humans, but where is the solution?
How can mankind, overnight stop exponential (that famous hockey stick everyone likes to see) oxygen growth? Very suspicious. There are some pretty bad sources of information out there about oxygen over time. Here is one I trust: <a href="http://dk6qunh1hkthr.cloudfront.net/content/nips/25/5/272/F1.medium.gif" rel="nofollow">http://dk6qunh1hkthr.cloudfront.net/content/nips/25/5/272/F1...</a>
And, since we are allowed to use graphs rhetorically rather than discuss complicated topics like adults... what's <i>really</i> causing the murder rate to decline?<p><a href="http://gizmodo.com/5977989/internet-explorer-vs-murder-rate-will-be-your-favorite-chart-today" rel="nofollow">http://gizmodo.com/5977989/internet-explorer-vs-murder-rate-...</a>
i read an article a while back on the economist which suggested that if you look at a longer span (much longer than 1880) you will find that this is a natural cycle that the Earth/Sun go through. We just happen to be at that point in the cycle. i really doubt we humans can affect climate changes in any way. An interactive colourful plot doesn't convince me.