Could people survive intense global warming?
If I'm understanding the sense of the question, I'm guessing probably not.
@JanDoggen in comments, and answers from @Larethian and @kutschkem, all make a point of questioning how fast the change takes place. This is a key parameter: given a long enough timeframe, survival of the human species at these temperatures is much more plausible. However, because of the way the question was phrased, I'm going to give an answer that assumes an extremely fast warm-up: 50° Fahrenheit (28° Celsius) in no more than 200 years. That seems implausible in planetological terms. But hey. This is Worldbuilding.SE, and we traffic in counterfactuals all the time. :-)
Disclaimer #2: Just to be clear on one thing: My answer doesn't apply to the actual world we live in, because neither does the question in the first place. @abcde is asking an interesting worldbuilding hypothetical, and I'm treating it with the respect it deserves.
(I feel I have to say this because, in my experience, questions like this tend to activate our genuine concerns about our primary world. This can make sound reasoning difficult, and carry the discussion off-track. Arguing our opinions about what's actually going to happen to us and our inheritors would step all over the original question and not be particularly helpful to @abcde.)
Why humans probably wouldn't survive such an intense global warming event: This is a question of planetary ecology.
With a tip of the hat to @JackAidley and @jamesqf, the question of human survival is less a question of how you find a survivable latitude/altitude in the rapidly heating world. It's about what happens in the years after you've arrived.
Many of the answers here assume, rightly, that humans would have to migrate for survival. Migration is hard;
but let's talk about the survivors. Let's talk about the skilled, prepared, and extremely lucky people who actually make it to some reasonable place in northern or southern uplands.
Suppose you're one of those lucky ones. You've found a place. Now what are you going to do for food? Never mind medicine, weapons, shelter, etc, and let's take sufficient drinking water as a given: if you don't have food you won't live.
Humans are, in the short term, a whole lot more agile and adaptable than their food base.
Humans can travel; farms and gardens and orchards cannot. The best you could have done would have been to carry a lot of seeds - since you are, by definition, lucky, you didn't have to eat your seeds on the march - and to bring some skilled agriculturalists with you.
So, you plant your crops. And most of them die.
They die because
they need nutrients that they can't get, or
because the winds are too savage, or
because the cycle of drought and flood is too extreme, or
because rampaging pests that you have no idea how to handle kill them.
In other words, your food crops are not adapted to the new local environment, and cannot adapt because the environment is still unstable.
If you look around for native vegetation that has edible parts, you're probably not going to find anything, because the changing climate has probably already killed a lot of the local species. (This local ecological collapse probably has a lot to do with why you can't find those nutrients your crops need.)
...So maybe you brought animals with you?
Herds and flocks of domesticated animals are a lot more difficult to take with you on your long march. Many of them wouldn't have made it; but remember: you are one of the unreasonably lucky ones, so you have enough of a herd to form a stable food base for your little community of settlers.
Now. What will those animals eat?
You need a lot of grazing to support a large herbivore. (You should see what just two of my horses do to the grass in their fairly generously sized paddock.) Even under reasonably stable conditions, grazing animals will eat a lot of pasture down, which is why pasturage needs to be rotated several times during growing season.
How much pasturage can you count on when there's a drought? Or a flood? Or a blight? All of which will be happening.
Then: what do they eat in the winter? Did you - despite the probable insufficiency of pasturage - also manage to get enough hay mown in the summer that you can feed your animals the whole winter through (which means, until pasture has grown enough to let the animals graze?)
And yes, growing seasons will be an issue: Even in a rapidly warming climate, you'll have colder times; and even if your winters remain warmer, plants don't feed on warmth, they feed on sunlight. If you've gone far enough north or far enough south, you've got parts of the year in which insolation is so weak that you won't get much to grow.
You can't run away from ecological collapse. The weather patterns will remain crazy. The pests that attack and kill your crops and animals will remain r-selected and thus prone to wild outbursts of population. And the organisms best suited to survival in an unstable environment are microorganisms: bacteria, viruses, yeast, fungi. Things that will kill you and your attempts at sustaining a food population
Even @GrandmasterB, in the most staunchly optimistic answer, notes correctly that
"The biggest impact I think would be the years following as agriculture tries to adapt." (Emphasis mine.)
In this unusually fast warming scenario, agriculture, along with other means of obtaining food over time such as hunting, fishing, and animal husbandry, will all fail because of the ecological collapse.
Humans in an intense global warming event would die off, probably, because they couldn't sustain themselves and their food supply over the long term.
Kudos on this one to @jamesqf. He deserves credit for a lot of key insights:
Mentioning the Permian/Triassic extinction, in which a worldwide ecological collapse brought life to a very rudimentary state.
Mentioning the possibility of another Ocean Anoxic Event, which would disastrously prolong any post-warming ecological collapse.
And, probably most powerfully, the comment that says "And that's my basic point: humans are supported by a lot of mostly unappreciated ecosystem. How much of it can you knock out before it collapses?"