This was triggered by a fellow that teaches statistics, and yet he recently denied the reality of AGW.
One knows, respectable people that have a university degree in math or something and they seem intelligent until they open their mouths on global warming, and deny AGW.
One debates politics and philosophy, but there is no debate over the basics of “Climate Science”. In climate science, one goes out and measures – there are no debates. (Well, maybe some back and forth while we wait for the paper(s) to get through peer review.) A basic text on the topic is http://forecast.uchicago.edu/ by David Archer.
However, there are a number of folks paid by the fossil fuel industry slinking around. They are well paid by the fossil fuel industry to lie, and sow doubt and deceit. However, that is deceit, lying, and fraud, not debate. See (http://www.merchantsofdoubt.org/ ) There are another group that see AGW as a conspiracy to impose more government controls. There is another goup in denial just because AGW is so terrible.
When, I was chemistry major, in 1972, AGW was an accepted fact, but everyone in the class had to prove it again (but only to slide rule accuracy.) (We were all Republicans. We did hard science, with real facts. In those days, the Democrats were over the social sciences.) IPCC AR5 is driven by a reality that has already been set in motion – greenhouse gases that have already been released. 180 governments have signed on to this concept. Of course, governments sign on to many things that do not happen, but future warming caused by those greenhouse gases and the additional greenhouse gases that we continue to release will trigger events that will scare Americans (even you) into accepting the reality of AGW. Every bit of new research shows that these changes are coming faster that previously stated by the IPCC. See for example http://www.eenews.net/stories/1060012729
and http://www.washingtonpost.com/news/morning-mix/wp/2015/01/15/the-rate-of-sea-level-rise-is-far-worse-than-previously-thought-study-says/ . Why be among the last to understand what is going on? AR5 is something every person with pretensions of understanding the modern world needs to understand in detail. At least, read the Summary for Policy Makers. I assure you that King Salman of Saudi Arabia has read it and been personally briefed by the diplomats from the Lima Climate Conference. And, a variety of business leaders are pushing similar goals. See for example: http://thinkprogress.org/climate/2015/02/05/3619802/ceos-are-important-people/
When I did risk management at Bechtel, I kept a list of 300 things that could go wrong on a Bechtel Project. These ranged from volcanoes and asteroids to traffic accidents and falls in the home. Big volcanoes occur rarely. AGW is here. Its probability is 1/1. It may be more or less intense, but it is here, and it will get more intense. So, in likelihood of occurring, AGW beats big volcanoes and asteroids. AGW at its most intense levels can almost certainly kill 7 billion people. Nothing else, except big volcanoes and asteroids even comes close. Sea Level Rise takes out critical infrastructure that is needed for everything. All microprocessors are bedded in gray plastic that is made at ~300 facilities mostly in Indonesia and Malaysia. The microprocessors are in parts and repair parts for factories, trucks, cars, computers, internet, and telecommunication switches. 6 meters of sea level rise takes out most of the gray plastic makers. And, everything sold at a WalMart is made in factories that need the microprocessors. If you ever need anything that might ever be sold at Walmart, then you also need gray plastic. And, most of the makers of synthetic fibers – e.g., clothes and truck tires, are also made at, or near sea level. If you want to jack those plants up or move them away from the beach then you will need high pressure steel pipe. The high pressure steel pipe is mostly made at the Shaw Plant outside of Houston. It is ~25 meters above sea level, but 3 meters of sea level rise blocks highway access to the port and sewage treatment. Oh, and financing for all the fix-up will have to come from some place other than NYC, London, Tokyo, or Singapore. These cities will all be flooded and scrambling for resources. As will the airports at Oakland, SF, NYC. . . .. And, a few feet of sea level rise takes out the factories that produce fertilizer and pesticides. Without fertilizer and pesticides, farmers cannot grow food. So a little sea level rise (few meters) means no food and no truck tires to move it around. We should be planning to save a few people and some infrastructure – intense AGW is a “near term” (several decades) certainty unless we change our ways. Whatever it costs, stopping any little part of it is cheaper than killing everyone and destroying everything. We are in a hole, and we need to stop digging.
Talking about 3 or 6 meters of sea level rise seems very silly in the context of the less than 5 mm/yr of sea level rise in recent years. Except that in the last interglacial, sea level rose 20 meters in 500 years. We do not know if that sea level rise was gradual or occurred as a few abrupt sea level rise events. And current climate forcing is now much greater than during that interglacial, so we should not be surprised by very large, abrupt sea level rise events. Uncertainly is not our friend. If we trigger clathrate releases, then we could have very large global warming, very quickly. The fact that so much liquid water is moving though the Greenland Ice Sheet, so rapidly, is indicative that stability of the Greenland Ice Sheet could be decades rather than millennia.
A large aquifer was found in Greenland (http://www.nasa.gov/content/goddard/enormous-aquifer-discovered-under-greenland-ice-sheet/#.VNuY0fnF-CM ) and the write up about it talks about it storing enough water to raise sea level ~0.4 mm. However, it’s drainage is likely to be rapid and carry with it the snow over the aquifer and to erode the 2 km thick ice under the aquifer. That ice acts as bulwark supporting other, higher ice which will flow toward the sea if the ice under the aquifer is eroded. Thus, a 0.4 mm estimate of sea level rise for the drainage of the aquifer is not an honest and realistic estimate of the total sea level rise event that can be expected when the aquifer drains.
Currently the water in the aquifer is super cooled by the melt under pressure of the firn over the aquifer. When the aquifer fills above the firn, then it will warm and hydro fracture the ice under it in a sudden drainage event. Or, the aquifer will rise above the level of the sills trapping it and the overflow will release enough heat (from potential energy) to erode the sill and the ice under it. In any case, an intra glacial aquifer is not a stable structure in a time frame of years.
As you may know, I have worked with nuclear materials, and I wrote much of the US DOE’s manual on the decontamination and demolition of radioactively contaminated facilities. In this, context, I expect that very intense AGW would have a broader and longer lived effect on human civilization than a major thermonuclear war with resulting Nuclear Winter, and substantial radioactive contamination of all countries with nuclear arsenals. However bad a nuclear war could be, very intense AGW could be worse. We need to put more focused effort on avoiding AGW, than we have ever applied to avoiding nuclear war. Compared to AGW, ISIL is nothing.
I differ from most scientists in having worked on major infrastructure projects at Bechtel, and I understand how long it takes to plan and implement new technologies. Thus, I am more eager to get people past understanding global warming, and on to planning and implementation. We have a lot to do and a short time to do it. In 2007, IPCC AR4 told us the Arctic Sea Ice would remain intact for 80 years, and the great Ice sheets would last for millennia. But in 2007 we lost a quarter of our Arctic sea ice. In 2009, we had https://www.youtube.com/watch?v=hC3VTgIPoGU, which tells us that glaciers can retreat much faster than the IPCC considered plausible only 2 years earlier. In 2014, we had http://www.leeds.ac.uk/news/article/3654/arctic_ice_cap_slides_into_the_ocean. New papers, just being published, regarding the 2012 melt season on Greenland suggest that I am correct about the urgency of the issue. See http://www.scientificamerican.com/article/surprise-lake-sheds-light-on-underbelly-of-greenland-s-ice/ .
Nor do the IPCC climate models include carbon feedback. A summary of one carbon issue is at http://www.wunderground.com/resources/climate/melting_permafrost.asp. And there are clathrates e.g., http://arctic-news.blogspot.com/2014/08/horrific-methane-eruptions-in-east-siberian-sea.html . (I do think David Archer is too reticent on clathrates.)
Show me an (IPCC) climate model that predicts these behaviors, and I will grant you that I am “alarmist.” The IPCC is not “wrong”, rather it is exceptionally conservative and carefully reticent because everything is reviewed by diplomats and lawyers. My models do predict abrupt ice behaviors. It is the stuff I learned in ChemE, 44 years ago. And it is stuff that Feynman told his (freshman) Physics X class 10 years earlier. There is no reason what-so-ever for it not to be in the IPCC models – except that it upsets people by disrupting preconceptions, and the reviewing diplomats dislike disruptions. Austfonna is only 500 miles from Greenland, so another Arctic Sea Ice loss event like 2007-2012, and we could have high speed flows off of the GIS within 20 years. You see, I am not an alarmist, I just do my home work, and I do not see uncertainty as a friend.
Today, the scientific basis of global warming is just as strong as the scientific basis of gravity, and to deny global warming is to sound as stupid as somebody that denies gravity. You can deny gravity, but dropping a cannon ball on your foot will still hurt just as much. You can deny human caused global warming, but it will affect you just the same. The “theory of gravity” allows one to predict the path of the cannon ball, just like the “theory of global” warming allow one to predict the effects and impacts of global warming.
Some of the measures in climate science require statistics to be useful. This has been done, and the peer reviewed papers can be found in the reference lists of IPCC publications (http://www.ipcc.ch/ ). These papers show AGW is not cyclical and is human caused. While many of the papers (individually) have confidence levels of only 95%, multiple lines of evidence give us very high over all confidence – beyond dispute.
A good display of statistics can be found at http://www.ted.com/talks/hans_rosling_shows_the_best_stats_you_ve_ever_seen. Unless you do your homework, you become a victim of your preconceptions. Population dynamics are at the root of the global warming problem – your preconceptions keep you from seeing how many people have been burning fossil fuels and how much they have been burning compared to the finite volumes of the atmosphere and carbon cycles. Good environmental statistics are at https://tamino.wordpress.com/ . There, Tamino explains what is wrong with the environmental statistics that you see in the mass media and certain blogs. His background is statistical analysis of satellite data streams to pull real information out of noisy data. He understands the measures of the world and he is more likely to tell the truth than folks that have fossil fuel companies as both advertisers and readers.
In Climategate, the merchants of doubt, are now losing lawsuits and are being found guilty of libel. Their headlines were lies, and they are being held accountable. http://www.salon.com/2012/10/24/climategate_scientist_sues_national_review_for_libel/ and http://www.motherjones.com/environment/2014/01/michael-mann-climategate-court-victory and http://www.kelownanow.com/watercooler/news/news/Provincial/15/02/07/MLA_Awarded_50_000_in_Defamation_Case_Against_National_Post . The merchants of doubt focus on the flaws in one paper, while ignoring other papers that address those flaws. It is worth using https://scholar.google.com/ to find such deceits. Hundreds of points supported in thousands of papers would have to be over-turned to put global warming or its human causes in doubt.
AGW has not paused or stopped. http://thinkprogress.org/climate/2015/02/02/3617852/hottest-decade-record-groundhog/ Most of the heat from AGW ends up in the oceans, and since sea level indicates both the sensible heat in the ocean and the heat of fusion absorbed by land ice, sea level is the single best indicator of total heat in the Earth System. And sea level is at historic highs, and rising faster than ever previously recorded by man. (Nature 517, 481–484 (22 January 2015, doi:10.1038/nature14093)
To quote the Saudi Oil Minister, "The stone age did not end because they ran out of stones, The stone age ended because they found something better. The oil age will not end because we run out of oil, it will end when we find something better." We have actually found things that are better than than oil and coal. We just need to start using them.