Realistic over-heating

The other day I wrote about the swallows having returned to Finland, well this almost true as there is one swallow that has been sighted, it must be have been the first pioneering scout arriving and but today more of them arrived.
And 10 new species of butterflies are reported to have landed in Finland which means more insects for the birds to eat.

According to the latest statistics the unemployment in April has decreased compared to last year and more people are now working with most of them in the private sector. Out of a population of more than 5 millions only just a little less than 2 ½ millions are employed so the rest must be the unemployed, children, students and retired. Just about half and half.

This means Finland must be doing well but according to the new minister of finances we must be careful as “over-heating is realistic for the time being” and the income tax-levels won’t be lowered as promised until later on, in the end of the four year period of this government just before the next elections.

If more people have got jobs and the taxes are lower, then they have more money to spend and the economy is doing well as money is moving with the possible result of even more jobs getting created.

What on earth is this over-heating? I do know about global warming but that is not what he is talking about, or an engine over-heating, but how does the economy over-heat?!?