Gulf Stream may be slowing - should we be worried?

Sunnuntai 15.4.2018 klo 17.10 - Mikko Nikinmaa

The weather in Europe has been very peculiar in recent years. Heat waves, long cold spells, storms and extremely heavy rain have been common - it has become more a regularity than an exception to have strange weather. While the reason for this cannot be given for certain, based on recent articles in Nature (D. J. R. Thornalley et al. Nature 556, 227–230; 2018 and L. Caesar et al. Nature 556, 191–196; 2018), it is tempting to speculate that the sequence of events may be the following. 

1. Increasing temperature causes ice to melt. (Ice is always salt-free)

2. The water from melting ice causes the arctic seawater to have decreased salinity.

3. Decreased salinity slows down the Atlantic circulation. Also the locations of circulation are affected.

4. The climate has been relatively stable for more than a thousand years, because the Atlantic circulation has been stable.

5. Because the changes in Atlantic circulation are unprecedent, the associated weather phenomena cannot be predicted.