We can quibble about how much methane will rise from the thawed and warmed tundra and will erupt from methane hydrate deposits on the ocean floor, and exactly how long it will last in the atmosphere. But every additional warming brings us closer to our species thermal limit.
Methane is a powerful greenhouse gas. Despite its short atmospheric half life of 12 years, methane has a global warming potential of 86 over 20 years and 34 over 100 years (IPCC, 2013). The sudden release of large amounts of natural gas from methane clathrate deposits has been hypothesized as a cause of past and possibly future climate changes. Events possibly linked in this way are the Permian-Triassic extinction event and the Paleocene-Eocene Thermal Maximum. — Wikipedia
IPCC = International Panel on Climate Change
https://blogs.scientificamerican.com/plugged-in/methane-hydrates-bigger-than-shale-gas-game-over-for-the-environment/
https://en.wikipedia.org/wiki/Methane_clathrate
Some qestions i have for anyone with environmental and weather sciences knowladge is: — XanderTheGrey
Can the relase of methane cause widespread increase in forrest fires and how does it work?
By raising the average temperature of a climate area, the soils dry out (and with it, the trees eventually) and warmer winters allow insect vectors to survive. Greater insect infestation leads to more tree diseases, and more dead trees. Millions of acres of dead and/or dry trees are a forest fire hazard under any circumstances.
I don't know where you live, but Minnesota and surrounding states have had very poor quality air on some days from fires which are 1000 to 2000 miles away. In some cases the smoke was at ground level all day.
Can it cause an increase in hurricanes and or tornadoes and how does it work?
Oceans and land in a warmer climate have more thermal energy stored up in it, and thermal energy (along with other factors) drives cyclonic storms. So, yes.
Will it effect lightning? In what way, and how?
The more storms, the more lightning. Methane won't have a direct effect on lightning.
What temperature can a human being survive at individually?
There is the "wet bulb temperature" -- the lowest temperature that can be achieved by evaporation. So, if it is 100% relative humidity, and the temperature is 95º F, a person will not be able to cool down below 95º. As the temperature rises above 95º F, the individual's temperature will rise with it. If the temperature rises to 106º or 108º, with saturated humidity, the person will begin to over heat and will die at some not very distant point (oh... 15 to 60 minutes, depending).
Why aren't more people dying, if this is so? Two reasons: Mad dogs and Englishmen go out in the midday sun. Just about everybody else stays in the shade. That's one. The other reason is that it isn't very often 100% humidity and 110º F. People can survive 135º F if the humidity is low -- because they can evaporate away heat.
Most places aren't going to experience these kinds of lethal "wet bulb temperature" levels. But the river valleys of southeast Asia will, and not in the far distant future. About 1.5 billion people live in these river valleys, and a lot of their food grows there. If people can't work the fields, they will die of heat stroke first, and if no agriculture, then starvation.
Other areas will have survival problems too. The SW U.S. won't experience web bulb temperatures like Bangladesh will, but even at 0% relative humidity and temperatures of 125 all day, everything is dead before too long. (Hot air and desiccation can kill things as well as saturated humidity and somewhat temperatures).