Relation $\Delta Unemployment$ and $\Delta GDPgrowth$ I have studied the development of the difference in unemployment and the difference in the growth of real GDP in the Netherlands over the years 1963-2016. 

From the picture it seems like a change in unemployment has a positive effect/predicts a change in GDP growth. How is this possible? Has this to do with the fact that unemployment is a lagging variable?
Well it seems like you are observing somthing consistent with  Okun's Law which reveals empirically negative relationship between Unemployment and GDP.

As Donald Freeman states in the conclusion to his paper titled paper Regional tests of Okun's law


  Okun's law is one of the more enduring stylistic facts of U.S. macroeconomics, having
  withstood numerous tests in the almost four decades since it was first promulgated by
  Arthur Okun.