Judith Rees will take up the post from 2 May until a permanent director is appointed.
She is currently director of the Grantham Research Institute on Climate Change and the Environment at the LSE, and was pro-director of the school from 1998 to 2004.
An expert on adaptation to climate change and the management of environmental risk and resources, especially water, Professor Rees has also served as an adviser to the World Bank.
Her appointment comes in the wake of Sir Howard’s decision to step down as director of the LSE earlier this month amid protests over its Libya links.
The LSE accepted a ?1.5 million donation in 2009 from the Gaddafi International Charity and Development Foundation, which is headed by Saif Gaddafi, an LSE graduate and the son of Libyan leader Mu’ammer Gaddafi.
Lord Woolf has been asked to head an independent inquiry into the affair, which will also look at the academic authenticity of Saif Gaddafi’s PhD thesis.
Commenting today on her appointment, Professor Rees said: “It will be an honour to help steer the school during this interim period when we will have a number of major issues to deal with including the important work of the independent Woolf inquiry, the changing nature of higher education funding and the appointment process of a new, permanent director.
“The core business of the LSE is world-class research and outstanding teaching. I will do everything I can to ensure this very special institution remains in the first rank of the world’s universities. Howard Davies has been an outstanding leader in this and other respects and will be a hard act to follow,” Professor Rees said.