Economic losses from disasters fell to an estimated $US44 billion ($55.78 billion) in the first half from $US117 billion ($148.6 billion) in the corresponding period last year, according to a preliminary Sigma report from Swiss Re.

The global figure is well below the first-half average of $US120 billion ($152.41 billion) over the past decade.

About $US23 billion ($29.21 billion) of the losses were insured, Swiss Re says.

Global natural catastrophe losses were $US41 billion ($52.03 billion), down from $US110 billion ($139.57 billion), with $US3 billion ($3.8 billion) attributed to man-made disasters.

Insured losses from natural catastrophes decreased to $US20 billion ($25.36 billion) from $US30 billion ($38.04 billion), while insured losses from man-made disasters fell to $US3 billion from $US6 billion ($7.6 billion).

An estimated 4400 people died or disappeared in disasters, compared with 4800 in the first six months of last year.

In the US, a four-day storm hit Colorado and southern and central states in May, causing economic losses of $US2.2 billion ($2.79 billion) and insured losses of $US1.9 billion ($2.4 billion). A high number of smaller storms and weather events in the US led to insured losses of about $US16 billion ($20.29 billion) from an overall bill of $US23 billion ($29.16 billion).

Swiss Re Chief Economist Kurt Karl says it is fortunate most US households are insured against wind risk.

Cyclone Debbie was the most costly event outside the US, with insured losses of $US1.3 billion ($1.64 billion), according to Swiss Re.