Third century AD climatic blip/ event

At the Egyptian newspaper Al Ahram Weekly (see http://weekly.ahram.org.eg/print/2010/997/cu4.htm ) there is a couple of pages on the Kushite kingdom based at Meroe, contemporary the Greeks and Romans. From a lot of evidence I picked out the fact the kingdom entered a phase of decline in the 3rd century AD – which must be significant. Although it continued for another 100 years or so, eventually defeated by Ethiopia (the highland kingdom) the fact that it foundered at the same time the Roman Empire experienced a 20 to 30 year period of problems, and general decline, must be significant.