The Committee on Climate Change (CCC) has urged the UK government to act now to reduce carbon emissions and tackle climate change.
The CCC said many policies designed to reduce future emissions would expire at the end of this parliament and uncertainty created by the lack of policies after 2020 would lead to failure to meet legal obligations to cut emissions.
In a report to the government covering progress towards meeting carbon reduction budgets and climate change, the CCC identified a number of risks around water scarcity, flood risk, heat stress and impacts on agriculture.
"The frequency and intensity of flooding, heatwaves, and droughts, is anticipated to increase with climate change," said the report.
The CCC set out a number of recommendations including extending funding on low-carbon electricity generation to 2025, supporting low-emission vehicles to save drivers money, agreeing on an action plan that delivers low-carbon heat and energy efficiency and preserving the fertility and organic content of soils.
Lord Deben, CCC chairman, said: "This government has a unique opportunity to shape climate policy through the 2020s. It must act now to set out how it plans to keep the UK on track.
"Acting early will help to reduce costs to households, business and the exchequer. It will improve people's health and wellbeing and create opportunities for business in manufacturing and in the service sector."
A spokesman at the Department of Energy and Climate Change said: "We are committed to meeting our climate change target of an 80% emissions reduction by 2050. We have already made great strides to that goal, with emissions down 30% since 1990.
"There's still much work to do and we will continue to power our move to a low-carbon economy at best value to consumers."