Research topic already covered, change direction or what? The previous days i begun with a research project on economic impact of physical disasters, and in the mean time , I found a paper with the same topic published 10 years ago (Sample period 1980-2003). My question is whether i should continue my research ( Which has similar methology) or change direction. Are there copyright issues even if I mention the previous work in the abstract? My sample period, on the other hand will be a 2005-2017.
You can cite the previous paper. You should consider whether your work contributes to the literature in addition to the previous paper. If you proceed, you can explicitly explain how your paper provides a novel contribution during your introduction. 

Some possible places you could extend the previous work might be:


Making changes to the methodology
Updating the paper for more recent results
Extending the previous results
Further validating the previous results 
Examining the question historically 


You may also want to consider contacting the author of the previous paper; he may be willing to work with you. 

In short, you might want to revise your research question and paper slightly, but you can continue with your research if you give credit to previous paper and can convince journals that your paper is important.