Anthropogenic: "there's more snow falling in Antarctica than ice melting" says nothing about humans being responsible one way or the other.
Global: more snow falling in Antarctica says nothing about overall global conditions, e.g. average surface temperature. Changes in circulation patterns can cool one spot and warm another.
Warming: more snow falling in Antarctica does not, by itself, even say anything about temperatures in Antarctica. It's not like raising the average there (-49C) by a few degrees would turn snow into rain. It could however increase the likelihood of precipitation.
I fail to see how "part of Antarctica sees increased snowfall due to raising temperature" is an evidence against AGW. At best, its an evidence against cartoon-version strawman AGW where every corner of the world warms up by an equal amount and every ice in the world starts to slowly melt away at the same pace.
Right - because warming increases mass of water vapor that air can hold. Which there is plenty of in the ocean, so then all the slightly warmer air melting the exterior ice allows the air to pick up moisture. Then as the air moves over the interior, temperatures drop and snow falls leading to the accumulation of snow mass that has been observed.
For example,
(1) A novel physical mechanism is discovered that increases the surface temperature of the Earth without any relation to greenhouse gases. Moreover, the mechanism has such a characteristic that it was steadily increasing in the past fifty years or so, roughly matching mankind's CO2 emission by pure coincidence. (I.e., "mankind is fucked, the universe decided to kill us off" scenario.)
(2) Average global temperature starts to drop unexpectedly, and continues to drop for a decade or more (so that we can rule out yearly statistical noise), despite the increased level of CO2.
(3) A new natural source of CO2 is discovered, and it is determined that the atmospheric increase of CO2 so far was actually due to this natural source. At the same time, a new independent natural sink of CO2 is discovered, and it is also determined that all the CO2 mankind has been generating was actually consumed by this sink. Even more unexpectedly, this big CO2 producer/consumer pair, while being pretty much in lockstep until 2015, is shown to diverge starting 2015, which refutes the whole point of "Mankind is responsible for increased CO2" argument. (This actually sounds like a variation of (1), but still.)
(4) Fish stocks and marine ecosystem unexpectedly starts to rebound across the ocean, thanks to increased photosynthesis by marine microorganisms. Upon further research, this is found to be linked with increased CO2 level. (This will at least partially falsify "this is a bad thing" part.)
I know, these are tough scenarios, but falsifying established science is hard. Falsifying it in a way that disproves its original successful predictions is even harder: it almost never happens. (Even after General Relativity and Quantum Mechanics, if Newtonian mechanics had predicted a railway to be dangerously curved, it would still remain dangerous in exactly the same way.)
Your point (1) has a huge assumption about "kill us off". There's no sign that mankind is being killed off. We're doing just fine. The novel mechanism might be transient and the increases in CO2 might be found to reverse.
Sounds like you would actually prefer that scenario to the mundane scientific consensus, where all we have to do is demolish the fossil fuel industry, cut back CO2 emission, and hopefully we could keep the number of displaced people in the order of several millions by the end of this century. Well, to each his own.
> I know, these are tough scenarios, but falsifying established science is hard.
It is also very hard to falsify the theory that invisible pink unicorns are causing global warming. It's not necessarily a good thing that a theory is hard to falsify.
For 2): there has been a 15-year global warming pause, which none of the models predicted. With your definition 2), that's actually close to a falsification of AGW.
A point I do agree on, which was also the point of my comment: a 10 or 15 year period is too short to say anything about climate. A pertinent question is then: what is a long enough period?
http://www.noaanews.noaa.gov/stories2015/noaa-analysis-journ...
http://www.theguardian.com/environment/2015/jun/04/global-wa...
http://www.forbes.com/sites/jamesconca/2015/06/15/a-pause-in...
"Evidence Against a Global Warming Hiatus?"
based on the scientific paper titled
"Possible artifacts of data biases in the recent global surface warming hiatus"
Also, that is a single paper, based on adjusting historical temperature data for a single data set, which then shows less of a hiatus. Compare that to the fifth IPCC report, based on a large number of data sets and a very large number of studies, which states unequivocally
“[global temperature] has shown a much smaller increasing linear trend over the past 15 years [1998-2012] than over the past 30 to 60 years.”
No, it doesn't have to drop. It just has to not rise. Which is exactly what has been happening for close to two decades now.
Furthermore, the level of CO2 has not just increased--it has increased by close to the "business as usual" scenario in the models--i.e., the worst case scenario, which the models predicted would show significant temperature rise that has not happened. In other words, the models have already been falsified.
> falsifying established science is hard.
Climate science is not "established science" in the way that GR or QM is. Falsifying GR or QM within their established domains of validity would be extremely hard, yes--but that's because their established domains of validity are nailed down by mountains of evidence from controlled experiments that matches the theoretical predictions to ten or more decimal places. Climate science is not even close--not even within orders of magnitude--to that kind of accuracy.
In fact, we should not expect climate science to be anywhere close to GR and QM in accuracy, because it's still a fairly new science, its domain is very complex, and it's not possible to do controlled experiments in most of the domain. We can't re-start the Earth's climate of fifty years ago with slightly different initial conditions and see how it performs.
None of this, in itself, disqualifies climate science as a science, or means that climate scientists are not doing important work. But it does mean that climate science simply cannot make the kinds of claims that GR or QM make about what is going to happen if we do or don't do particular things. The honest thing for climate scientists to do would be to admit that.
In addition, this is an interactive page that lets you plot yearly global temperatures up to now. Now look at this graph and please tell me if temperature did not rise in the 21st century.
http://www.ncdc.noaa.gov/cag/time-series/global/globe/land_o...
Finally, this page [2] compares IPCC's 2001 prediction with observed temperatures up to 2010. Look at the graph titled "2001 Projections vs. Observations", and see how closely the prediction matches reality starting 2001. (Which is not surprising, considering that it's only 10 years.) And now ponder what would happen if this "trend" continues for another 90 years.
[1] http://www.csicop.org/si/show/has_global_warming_stopped/
[2] http://www.skepticalscience.com/lessons-from-past-climate-pr...
These aren't "graphs", they're histograms, and it's impossible to read any trend lines off of them. So they're useless for this discussion.
> Look at the graph titled "2001 Projections vs. Observations", and see how closely the prediction matches reality starting 2001.
First of all, since the IPCC TAR was published in 2001, anything before 2001 is not a "projection", it's a "fit of model to past data". (And notice that the model does not fit all of the past data very well; before the mid-1900s in Figure 2 there is significant divergence. A model that can't retrodict the past can't be expected to predict the future.)
Second, these graphs are useless because they just give the "prediction" as a single line, with no error bars and no differentiation between the different sets of model runs that were based on different assumptions for how CO2 would rise. In other words, these graphs are spin, not science.
That's just not true: http://www.realclimate.org/index.php/archives/2014/12/recent...
http://wattsupwiththat.com/2015/06/03/el-nino-strengthens-th...
Also note the graph showing the increasing mismatch between models and observations.
Of course many will object to my choice of source, just as I objected to RealClimate as a source. But the data set used is an "official" one (the RSS satellite data), though not one you hear as much about.
Furthermore, there are independent measurements of sea level changes showing how much it's rising per year, even if we don't know where it's coming from.
The real consequences of this finding are explained in the article:
"The good news is that Antarctica is not currently contributing to sea level rise, but is taking 0.23 millimeters per year away," Zwally said. "But this is also bad news. If the 0.27 millimeters per year of sea level rise attributed to Antarctica in the IPCC report is not really coming from Antarctica, there must be some other contribution to sea level rise that is not accounted for."
From the article, the ice accumulation seems to be from increased snowfall during the Holocene. How this will ultimately be affected by warming isn't clear, but for now it seems somewhat orthogonal to AGW.
[0] Instead, most mass loss from Antarctica appears to be at the margins and driven by ocean processes.
This is explained in the article.
The article explains that there are two competing processes affecting the total amount of ice in Antarctica. One is the process of formation of ice mass from snowfall, the rate of which has been steady for the past 10,000 years (this study has now measured it at 200 billion tons per year). This affects the total amount of ice across Eastern Antarctica and the interior. Unfortunately, this process has not _increased_ either.
The second process is the thinning of the glaciers. The rate of _this_ process has increased since 1992-2008 by 65 billion tons. As the article points out, if this continues, than Antarctica will begin to see a mass decrease.
I'm not entirely sure how this can be interpreted as a point against AGW, or what it has to do with the anthropogenic part at all, nor do I see how it can seen as evidence against simple GW (regardless of cause), as the melting process is still increasing. At best, it can be seen as evidence that things haven't gotten out of hand yet. Now, if the Antartic snow growth was accelerating, then we could start arguing that we don't need to worry about CO2 increases, as the planet will just compensate any shift with some (unknown) homeostatic counter process. However, as it stands, this report provides no evidence for that.
http://muller.lbl.gov/pages/IceAgeBook/history_of_climate.ht...
i.e. AGW might be a not entirely bad thing, from the northern hemisphere's limited point of view at least, were it to be sufficiently finely calibrated to maintain the interglacial period indefinitely.(I suppose if the many worlds interpretation is correct, there's got to be at least one earth that gets lucky.)
However be aware, there is also a theory floating around that it might in fact trigger the next ice age, if it shuts down the global conveyor belt currents, in particular the gulf stream.
http://science.nasa.gov/science-news/science-at-nasa/2004/05...
And that, as much as anything, is why it's called climate change, rather than global warming these days.
(emphasis original)
Who cares? Once you've asked whether something is bad, why on earth would it matter whether humans are causing it? It matters to the environmentalist movement, because it is a tenet of that movement that the same change is good if not metaphysically related to humans but bad if it is. That's not a viewpoint I'd endorse, though.
That's a misconception you're holding onto. Those working on mitigating carbon in the atmosphere don't' care what the source of the carbon is. Whether we caused it or not simply doesn't matter.
> If we didn't cause it, the whole edifice crumbles.
The attempts to stop a calamity are worthwhile regardless of the original source of the calamity. Engineering the environment does not depend on whether we think we accidentally engineered it before.
Climate change is the more broader and comprehensive view of man's impact on the current climate and it goes far beyond greenhouse gases and the common causes of global warming. Greenland for example which is one of the current largest contributors to the rise of sea level is melting not only due to warmer sea and air temperatures but as latest studies show due to changes in the albedo mainly due to (black) carbon deposits in the ice.
The change in the albedo of glaciers in some areas was not considered until fairly recently to be the major contributor and catalyst to them melting, and this also affects land glaciers which were previously considered more resilient to sea temperature changes and could even serve to mitigate or dampen the affect.
Climate change also deals with other issues such as massive deforestation, salinity and acidity changes in water which affect gas absorption which can lead to thermal and molecular expansion, as well as many other things.
The climate is complicated and the fact that moisture from the air is deposited on land based ice in Antarctica doesn't change the fact that man made climate change is a real fact, heck pretty much all climate change models actually predicted that land ice thickness would increase when sea ice is lost at increasing rates as the increased moisture of the air would increase precipitation, and precipitation over Antarctica isn't a good thing it means that the air is getting considerably warmer because cold air has almost no capacity for water vapor[0].
This of course also that droughts would increase in places that we actually need them because air is getting warmer and the global jet streams whisk it away and before when the air would normally get colder and lose it's water vapor capacity and condense which would make it rain over land and most importantly populated areas we see now more precipitation in places like Antarctica and worse the oceans.
http://web.gccaz.edu/~lnewman/gph111/topic_units/Labs_all/Wa...
This issue is way too complicated which is probably one of it's biggest issues because people who like to dig their heads into the sand like to use simple anecdotes to disproof something which sadly we know too little about to understand, but enough to know that we should be quite afraid of.