These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Bellisario's Maxim: Emmerich has stated that the film was never intended to be scientifically accurate - the credits claim it was based on the book The Coming Global Superstorm, by Art Bell and Whitney Striber.
Critical Research Failure: There's a reason the main page quote is what it is. This movie's depiction of climatology is accurate in only one technical point; the planet Earth actually does have a climate.
Don't Shoot the Message: While real-life climatologists were glad to see the subject of climate change and global warming getting attention from Hollywood, they've expressed concern that the film's depiction of climate change might desensitize audiences to the reality of the issue.
This is especially troubling to a number of environmentalists as even serious discussions of climate change often go off the deep end in descriptions (claims of the poles melting overnight, our children never seeing snow) when the reality is that it will consist of single-digit changes in average temperature with potentially strong changes in rainfall.
Ensemble Dark Horse: Brian. Helps that he's pretty much one of the only funny characters in this movie.
The homeless man too.
"Funny Aneurysm" Moment / Hilarious in Hindsight: The movie bases its premise on the next Ice Age being caused by global warming. The record cold winter of late '09 / early '10 was pinned on global warming by some climatologists. It's known that global warming can cause a reduction in temperatures in the north, just not anywhere nearly as cold and fast as in the movie.
Tornadoes touched down briefly in Southern California in January 2010.
Depends which end of the political spectrum you're on, but the Vice President's comment about meeting with the head of FEMA as the film was released a year before Hurricane Katrina.
Seeing Manhattan flooded and battered by gale-force winds seems a lot grimmer to anyone who was in NYC for Superstorm Sandy.
It's been debated whether the North American Cold Wave of 2013-2014 was due to climate change (general conclusion: impossible to prove either way but it's a natural event that could have easily happened multiple times in the past without us knowing it), but many of the worst effects were uncomfortably reminiscent of the events depicted in the film.
Even more uncomfortably-so, now that 2014-2015 is seeing Boston buried even worse that Buffalo got it last winter.
Inferred Holocaust: As this video demonstrates, most of the Northern Hemisphere has become an Arctic wasteland, all surviving Americans have gone to Mexico, which won't be able to hold them all, leading to either an American uprising or Martial Law. Canada, Europe, and Russia are all stated or shown to have suffered a similar fate to the one depicted in the US, only worse (because they're further north). Europe is implied to have got hit particularly hard, as south for them would be the Mediterranean, so they were basically trapped. India and China aren't really mentioned but India at least (and parts of China) are probably far south enough the have escaped turning into an ice cube. So that's goodbye Europe (740 million), Russia (130 million), and Canada and most of the USA (call it 250 million?), plus an unknown amount of people in Asia and the victims of all the typhoons and tsunami around the world. It's not (quite) the end of the world, but you're looking at a death toll of at least a billion, possibly closer to 2 billion, with everything north of about 35' latitude now about as hospitable as the North Pole on a bad day.
And then you consider that the above list includes most of the world's core agricultural regions...
Potentially the fate of the astronauts trapped upon the International Space Station.
Not necessarily. There are a number of alternate landing sites for the Shuttle, some in the southern hemisphere. Their families, on the other hand...
All the storm effects are incredible, especially the Wall of Water in Manhattan.
The only visual downside in the movie is the CGI wolves which, for the most part, lack detail/complexity in their rendering. But there are still some moments where the wolves look great, such as the shots of them walking/running through the stairs.
What an Idiot: Many people over the course of the film. Most notably the Vice President, who dismisses Jack's advice they begin evacuating people, after he witnessed Los Angeles get destroyed by tornados.
Also the French woman that is more concerned about getting her passport than the fact that the streets are flooding and a huge wave is approaching.