I just returned to my hotel after attending my first day at this year's American Geophysical Union Fall Conference in San Francisco. The meeting started on Monday and runs through the entire week. It is the largest meeting by far for the Earth and Planetary Sciences with well over 12,000 scientists in attendance.
After listening in on this morning's session on Venus, and prior to the Venus poster session, I found myself with a couple of hours of unscheduled time. It didn't make sense to walk back to the hotel, as I would have to turn around an hour later and walk back the Moscone Conference Center. Instead, motivated by some recent discussions on internet fora, I decided to attend a few talks and browse a few poster presentations related to global and regional climate change.
It was a bit like coming home. My education is firmly grounded in the Earth and Atmospheric Sciences. All my graduate research was related to the Earth's atmosphere. It's only in the last decade that I transitioned to planetary work. Not surprisingly, I ran into a few old friends and grad school buddies that remained in the terrestrial scientific community. I was able to catch up on a few topics that I hadn't thought about for quite some time. I even took note of a few terrestrial studies that might have some application to the work I'm currently doing on Mars and Titan.
A picture paints a thousand words, but unfortunately the camera in phone decided to go kaput, so let me describe what I saw at the poster sessions, hopefully in less than a thousand words. Imagine a room the size of a football stadium. Now double it. This is roughly the size of the room allocated to display posters. Within this room are dozens of aisles of bulletin boards, numbered from one to approximately 2,000. Each day, the posters change, resulting in the display of roughly 10,000 scientific presentations over the conference period. [Edit: Turns out there are gaps in the numbering, so that actual number of posters is actually close to several thousand.] The aisles of posters are categorized into broad topics like "Planetary Science", "Atmospheric Science", "Seismology", etc. Within these broad categories there is further categorization into subfields such as "Climate Change", "Climate Observations", "Regional Modeling", "Stratospheric Dynamics", etc. In order to avoid mass congestion, poster presentations are scheduled on a staggered system; only about one-half of the room has active presentations at any given time, although all the posters are up for perusal. The scientific content in the room is massive.
A good fraction of the posters are related to climate and climate change. Some directly target the issue of anthropogenic global warming (AGW), some are tangentially related to AGW and investigate, for example, global and regional climate model accuracies. Other posters look at various observational records, while still others focus on the intersection of science and policy. Just about every angle on the AGW issue is covered in some manner.
Clearly, given what I've just described, it was not possible to read every poster in detail. Likewise, there are so many lectures on climate science, that they are often scheduled on top of one another; it's not possible to attend every talk. Still, most posters have a summary section or conclusion section that can be read in just a couple of minutes. Based on the talks I did attend, on reading some posters in detail, on reading most of the poster conclusions, and on talking with a variety of the presenters, there is only one possible conclusion that can be reached regarding the consensus of experts on AGW:
There is overwhelming scientific consensus on the issue of Anthropogenic Global Warming. That consensus is that humans are producing a warming of the climate due to the emission of CO2 and the positive climate feedbacks that result from that emission.
To deny this overwhelming consensus is to deny gravitation, the heliocentric model of the solar system, or the spheroidal nature of the Earth. Let me make it perfectly clear, however, that this is no way means that the consensus is correct. Neither is this consensus unanimous. There were clearly speakers and poster presentations that were contrary to the consensus, but they were in the minority by far. Really far.
I don't expect that the random qualitative sampling I did today would be much different than any other days, but I'll pop in on the climate presentations over the next few days just to confirm. If anything changes, I'll post an update.
The next time you hear someone forward the argument about a lack of consensus on AGW, tell them to go to the AGU meeting and collect some data. There is only one conclusion that can be reached after such an exercise. The conclusion is inescapable and irrefutable. The overwhelming consensus is that AGW is here. There may be other arguments against AGW, but the "lack of consensus" argument is dead on arrival.