  The relatively warm climate found in the North- Western Europe is due to the
gulf stream that circulates warm saline water from southern latitudes to
Europe. In North Atlantic ocean the stream gives out a large amount of heat,
cools down and sinks to the bottom to complete the Thermohaline circulation.
There is considerable debate on the stability of the stream to inputs of fresh
water from the melting ice in Greenland and Arctic. The circulation, being
switched off, will have massive impact on the climate of Europe.
Intergovernmental panel on climate change (IPCC) has warned of this danger in
its recent report. Our aim is to model the Thermohaline circulation at the
point where it sinks in the North-Atlantic. We create a two dimensional
discrete map modeling the salinity gradient and vertical velocity of the
stream. We look for how a perturbation in the form of fresh water release can
destabilise the circulation by pushing the velocity below a certain threshold.
