Читать книгу Carbon Counter - Mark Lynas - Страница 13

The Gulf Stream is one part of a massive interlinked conveyor belt of currents that takes heat around the global oceans. Consider that London lies further north than Vancouver in Canada, while northern Scotland is at the same latitude as southern Alaska – but in both cases Europe has a much milder climate, thanks to the warm ocean currents we enjoy.

This current loses its heat in the North Atlantic and Arctic Oceans, and the water sinks to the bottom of the ocean bed. This happens because colder water is more dense and salty, and therefore heavier, driving the movement of the ‘conveyor’. The fear is that global warming will lead to a fresher ocean surface in these sinking regions due to higher rainfall and melting ice, shutting off the crucial driving point of the ocean conveyor. Indeed, a slowing of the current has already been detected by scientists.

However, there is disagreement in the scientific community as to whether this slowing is just a blip or something more permanent. Most computer models do not suggest that the shutting down of the ocean circulation would lead to a new ice age in Europe, although our weather might still change dramatically. So the flash-freezing scenario played out in the movie The Day After Tomorrow is likely to remain fiction.

 Greenland tips into irreversible melt, accelerating sea-level rise and threatening coastal cities around the world.

 Polar bears, walruses and other ice-dependent marine mammals become extinct in the Arctic as the icecap disappears.

 Drought, fire and searing heat strike the Mediterranean basin.

 Declining snowfields threaten water supplies in California.

 A third of species worldwide face extinction as the climate changes.