Because it wouldn't be just a 10 degree (not sure where this number is coming from) average increase. It's a 10 degree average as calculated across an entire world full of extremes.
A 10 degree average is a huge increase in energy in the system, and that energy will be expressed in all sorts of ways. It'll be colder in winter due to an erratic jetstream pulling cold air down further than ever before, hurricanes will be bigger because of all that extra energy, summer storms will have that much more potential and the clouds will be able to hold way more water before bursting. But also because the atmosphere can hold more water it'll rain less, leading to drought.
The whole system will be energized, and the energy won't be evenly distributed. Our natural disasters will be massive.
A 10 degree average is a huge increase in energy in the system, and that energy will be expressed in all sorts of ways. It'll be colder in winter due to an erratic jetstream pulling cold air down further than ever before, hurricanes will be bigger because of all that extra energy, summer storms will have that much more potential and the clouds will be able to hold way more water before bursting. But also because the atmosphere can hold more water it'll rain less, leading to drought.
The whole system will be energized, and the energy won't be evenly distributed. Our natural disasters will be massive.