By Astrid Zweynert

BONN, Germany (Thomson Reuters Foundation) - National governments should give cities and towns more direct access to finance to tackle rapid urban growth and the threat posed by increasing natural disasters, the head of a global network of cities said on Wednesday.

Around the world, 55 percent of people live in urban areas, a number that is expected to rise to 70 percent by 2050.

The risk of man-made and natural disasters hitting fast-growing cities is rising, adding pressure on municipal authorities to protect residents through better planning, experts say.

"Cities are dealing with some of the biggest drivers of unsustainable development and faces enormous challenges that are increasingly difficult to manage," said Gino Van Begin, secretary general of ICLEI–Local Governments for Sustainability.

As cities represent more than two thirds of the global economy and 70 percent of global greenhouse gas emissions, the question is no longer whether sustainable urban development is essential, Van Begin told the Thomson Reuters Foundation.

"It is clear that we need sustainable cities because they ultimately protect and enhance daily life for all residents," he said as Resilient Cities 2016, an annual conference organised by ICLEI and attended by urban experts, campaigners and politicians from more than 40 countries, kicked off in Bonn, Germany.

Van Begin cited Surat in India as an example for forward-thinking approaches to resilience. The city developed India's first vector-borne disease surveillance system to counter risks from epidemics such as malaria and Zika.

The Swedish city of Karlstad made disaster risk reduction a top priority by integrating it into city planning and allocating part of its annual budget for investments in critical infrastructure, such as sewage and storm water management.

"We're seeing bold steps from cities but it's extremely difficult because local governments lack direct access to finance and control over spending," Van Begin said.

Most funding from bilateral development agencies or multilateral financial institutions must be channeled through and guaranteed by national governments, he said.

An added complication is that cities often do not have credit ratings and therefore are unable to borrow money directly on the market.

"It is critical and urgent to ensure that local governments are able to access and manage these funds and to direct investment in the most effective way to reduce their risk," Van Begin said.

Van Begin noted that new U.N. global development goals, the Sendai Framework on Disaster Risk Reduction and the Paris deal on climate change for the first time recognized cities as key drivers for a sustainable future.

Initiatives, such as the Green Climate Fund, are trying to address the needs of poorer nations to deal with climate change in the coming years, but financing urban resilience efforts at the local level is not a focus.

As global leaders prepare a new 20-year development plan for the world's urban areas, to be agreed a U.N. conference in Quito in October, Van Begin said he hoped the meeting in Ecuador will result in a more holistic approach to urban policies.

This must include a bigger focus on the growing number of people living in informal city settlements, he said.

"There is a lot of opportunity there to benefit from the human capital that population growth brings but we must make sure that cities are a key part of that discussion at all levels," he said.

A quarter of the world's urban population lives in slums where they are particularly vulnerable to disasters and lack rights due to lack of land titles, the United Nations says.

(Reporting by Astrid Zweynert; Editing by Katie Nguyen. Please credit the Thomson Reuters Foundation, the charitable arm of Thomson Reuters, which covers humanitarian news, women's rights, trafficking, property rights and climate change. Visit news.trust.org to see more stories)