Leaders from every country, from the largest to the smallest and most in need are gathered in Warsaw, Poland, for the latest round of climate change negotiations. They come together at a point in world history where greenhouse gases are reaching levels not seen for at least 800,000 years.

Their mission is to take a number of fundamental steps towards a critical climate change agreement in 2015, and they will achieve this by discussing ways to act immediately to curb greenhouse gas emissions, and by helping people adapt now to the effects of climate change.

While a renewed sense of urgency provides the backdrop for these negotiations, it is accompanied by a renewed sense of optimism.

The world today is politically, practically and economically different from four years ago when the last big attempt was made to achieve a global agreement on climate change.

The will to take action on climate change is growing. Not only for the environmental benefits, but for security, energy and governance reasons. On balance, although not everywhere, the political will among our leaders to act is growing and so is the public support and the expectation of leadership.

There are strong economic advantages for acting, beyond the fundamental one of radically reducing the consequences of climate change. We’ve seen increased investment in renewable energy throughout the world, driven by those who recognise that a transition to a low-carbon economy spurs economic growth and creates new job opportunities.

If we are to tackle climate change with the required urgency however, we must do more to increase and speed this transition. We need more investment — and more innovative methods of investment—in mitigation and adaptation initiatives.

It is entirely within our reach. An investment of just one or two per cent of global GDP means we can not only manage the risks of climate change, but also create a global economy that is clean, efficient and fundamentally sustainable.

We also know from past waves of major technological change that intense periods of creativity and innovation can transform the world, and we are already witnessing a new energy and industrial revolution take hold.

Since 2009, the costs of many clean energy sources have tumbled to record lows, triggering a boom in low-carbon technologies such as wind and solar. A record 115 gigawatts of renewable energy capacity was installed world-wide in 2012.

The geographical spread is also widening. No longer are clean energy technologies just limited to developed countries—China's investment in renewables jumped 22 per cent between 2011 and 2012, and significant investments were seen in a wide range of countries, such as Kenya, Morocco, Chile and South Africa.

The Middle East’s biggest solar power plant was officially inaugurated in Dubai with the aim of achieving 1,000 megawatts in output by 2030, equal to five per cent of the city’s total energy consumption. And Ethiopia’s recently-completed 120 megawatt wind farm is expected to produce 400 million kilowatt hours of electricity annually.

Today, millions of people work in the renewable energy sector and many more jobs will be created if clean energy investments are further accelerated and scaled-up.

We have seen other examples of innovative financing that are making immediate differences and paying increasing dividends. The United Nations’ Momentum for Change Initiative showcases such projects.

One example is the International Fund for Agriculture Development, which recently launched the world’s largest climate adaptation program to help millions of smallholder farmers worldwide. The scheme directs funds to smallholder farmers so they can access the tools and technologies to build resilience to climate change.

Another example is the work being done in Mexico, where climate change is being tackled by unlocking financing and increasing the number of mortgages to build low-carbon housing.

What these projects share is a recognition of the necessity for innovative and successful finance mechanisms and the political will to implement them. We need more of these projects—many more—and at a bigger scale. This works best if governments and businesses work collaboratively.

In September, the Global Commission on the Economy and Climate, and its flagship project, the New Climate Economy, was set up to foster and accelerate the transition to a low-carbon economy. The project, with the first report due in September 2014, will help governments, businesses and society make better-informed decisions about how to achieve economic prosperity while also combating climate change.

The groundswell of national initiatives both governmental and non-governmental is triggering a real momentum for change. However, while more decisive national action can take us far towards the goal of stabilising emissions in the atmosphere at acceptable levels, it is still not far enough.

Warsaw offers an opportunity for all governments, NGOs and corporations to embrace not only the environmental, governance and security advantages of addressing climate change, but the economic ones as well.

A new universal climate agreement is within our reach. With clear science and agencies and development banks and investors and subnational governments on board, Parties can join the rising momentum and move together towards success in 2015.

• Lord Stern of Brentford, a professor of economics and government at London School of Economics and Political Science and former chief economist of the World Bank, and Christian Figueres, executive secretary of the UN Framework Convention on Climate Change (UNFCCC)