It’s taken three years to write the script for the future of the world, but now it’s time for the much-anticipated performance to begin.

World leaders have negotiated and agreed an ambitious plan to end poverty and inequality in the next 15 years, adopting 17 Sustainable Development Goals (SDGs) at the UN as a road map to tackle the world’s most troubling problems.

While getting the 193 member nations to agree on priorities, scope and wording of the SDGs and their accompanying 169 targets was monumental, far more daunting is their implementation.

The toughest challenges are the sheer breadth of the agenda, finding ways to monitor and measure progress, and keeping the process transparent and accountable.

Added to those are the reluctance of some countries to address certain issues, with climate change and gender equality high up the agenda, not to mention the enormous trillion dollar price tag, say those involved in the sweeping project.

“Having been in government, I know managing 10 targets is difficult. Managing 169 targets is challenging for the most efficient government,” said David Miliband, president and CEO of the International Rescue Committee that runs humanitarian relief operations in more than 30 war-torn countries.

“The great danger is that the breadth of the targets becomes an excuse for not fulfilling the targets,” Miliband, a former British parliamentarian, told the Thomson Reuters Foundation.

Echoing that sentiment, Helen Clark, administrator of the United Nations Development Programme, said the role of the 169 targets is to bring the goals down to manageable bites. The targets range from halting deforestation to raising living standards and reducing child mortality.

“These sub-goals spell out in great detail what we need to do so that every year there is stock taking as to what we’ve been able to do,” said Clark, former New Zealand prime minister.

Managing 10 targets is difficult. Managing 169 targets is challenging for the most efficient government

Implementation will be monitored and reviewed with a set of global indicators to be agreed by next March.

Accountability and transparency are essential to coaxing private businesses to help put the goals into action, said Mogens Lykketoft, president of the UN General Assembly.

The private sector is expected to play a major role in enacting the SDGs which will cost an estimated $3 trillion a year at a time when most countries face budget constraints.

“We are far away from reaching the scale required, the trillions of dollars required in the next 15 years to make a decisive impact,” Lykketoft said.

With the SDGs relying heavily on the private sector, business will insist on countries having stable regulatory and taxation frameworks, he said.

While adoption of the SDGs featured world leaders expounding at length at UN podiums on their commitments to lofty aspirations, the fact is plenty of countries cannot or will not meet some of the most critical goals without public pressure or political change, experts say.

The US, for example, is among nations least likely to meet goals to end poverty and combat climate change, according to a study by Bertelsmann Stiftung, a German social responsibility foundation.

Holding the US back are such issues as its income gap, consumption behaviour and environmental protection, it said.

“Fossil fuels are an economic time bomb and the infrastructure and investments to support them will become stranded assets,” WWF’s Brown said.

“What we expect from large economies – like the US and China – is that they should be looking at the long term and making the right decisions in the short term.”

Other nations deemed likely to have trouble meeting the goals were Greece, Chile, Hungary, Turkey and Mexico, challenged by income gaps, lack of education, weak infrastructure, gender inequality, crime or extreme poverty, the German study said.

WaterAid America has identified 45 countries unlikely to succeed on the goal of ensuring water and sanitation “without dramatic change to political prioritisation and financing”.

“In many cases these are post-conflict states with weak governance, and limited ability to mobilise the methods of financing that are needed,” said Lisa Schechtman, WaterAid director of policy and advocacy.

British parliamentarian John Alderdice, who played a key role in the Northern Ireland peace process, said he was concerned that the global goals are not robust enough in promoting peace and good governance.

“At the moment people see themselves as being great leaders because they are conducting conflict, not because they are solving it and this provides a sense in the global community not of hope but of antagonism,” Alderdice told the Thomson Reuters Foundation in an interview.

Why do these goals matter?

The Sustainable Development Goals are a set of 17 goals and 169 targets aimed at resolving global social, economic and environmental problems.

To be met over the next 15 years, the SDGs replace the Millennium Development Goals (MDGs) which were adopted in 2000 and expire this year. Implementation of the new goals, requiring trillions of dollars in investment, will be monitored and reviewed using a set of global indicators to be agreed by March 2016.

Who decided the SDGs?

Governments came up with the idea at the Rio+20 conference on sustainable development in Brazil 2012. A working group with representatives of 70 nations drafted a proposed set of goals.

At the same time, the UN ran public consultations around the world and an online survey asking people about their priorities for the goals.

Why do we need them?

Some 795 million people still go hungry and around 800 million people live in extreme poverty, with fragile and conflict-torn states experiencing the highest poverty rates. Between 2008 and 2012, 144 million people were displaced from their homes by natural disasters, a number predicted to rise as the planet warms, bringing more extreme weather and rising seas. Water scarcity affects 40 per cent of the global population and is projected to increase. Some 946 million people still practice open defecation. Gender inequality persists and 57 million children still denied right to primary education.

How can things improve?

The 17 goals aim to achieve these wider aims by 2030 – end poverty and hunger everywhere; combat inequalities within and between countries; build peaceful, just and inclusive societies; protect human rights and promote gender equality and the empowerment of women and girls; ensure lasting protection of the planet and its natural resources; create conditions for sustainable, inclusive and sustained economic growth, shared prosperity and decent work for all.

What’s new and different?

The UN says the SDGs go much further than the previous goals, because they address the root causes of poverty and pledge to leave no one behind, including vulnerable groups.

They also emphasise the need to tackle climate change urgently and protect the environment through a shift to sustainability and wiser management of natural resources.

The SDGs are intended to be universal, applying to all countries rather than just the developing world.

They recognise the key role of the private sector in pursuing and financing sustainable development, in partnership with governments and civil society.

Sources: United Nations Development Programme and other UN agencies