The greenhouse effect is not a problem in itself; life depends on it. Water vapour, CO₂ and other gases trap part of the heat Earth radiates back towards space. Without them, the average surface temperature would be about −18 °C instead of roughly +15 °C today. Today's problem is how fast our emissions are strengthening it.
On 27 August 1883, the eruption of the Indonesian volcano Krakatoa was heard as far away as Rodrigues Island, nearly 4,800 km away. Its pressure wave was picked up by barometers worldwide and circled the globe several times. The tsunamis that followed killed more than 36,000 people.
The deepest known point in the ocean, Challenger Deep, lies roughly 10,900 m below the Pacific surface. Drop Everest in and its summit would still sit about 2 km underwater. Down there, the pressure is more than 1,000 times what you feel at sea level, roughly a tonne pressing on every square centimetre.