Although Kenya was not included in the sale, Douglas-Hamilton said any ivory sales immediately push up global demand, since elephants could be killed in Kenya and their tusks smuggled into a foreign stockpile.

Around 23,000 elephants live in Kenya but populations can be devastated by poaching within a couple of years. A recent survey in Chad showed its elephant population had declined from 3,800 to just over 600 in the past three years.

"The drought is one of nature's big events," he said. "It hits all animals, elephants, people and others but the ivory trade is much more serious and could do much more damage if it remains unchecked.