Federal Reserve Chairman, Alan Greenspan, warned Friday that recent gains in U.S. home prices, stock values and other forms of wealth may be temporary and could easily erode if long-term interest rates rise.
the dude is concerned about future economics
he is warning about something, clearly indicating concern
( z1 concern :ARG0 ( z2 economics :time ( z3 future ) ) :ARG1 ( z4 dude ) )