In Singapore, we named this year the Year of Climate Action, and we have done a lot.

We saw our Government pass the Carbon Pricing Bill, campaigns against single-use plastic, and many other events surrounding sustainability and climate change.

In the light of the special report by the Intergovernmental Panel on Climate Change, we need to keep this momentum going.

The report called for nations to take critical action within the next 12 years to conserve a safe and habitable future. It emphasised the need for deep systemic changes in the energy and finance sectors. Here in Singapore, a lot of focus has been put on governmental and individual action.

Institutions, too, have a lot of power to enact such systemic changes - particularly in creating an energy transition. Such a transition would be complex and require numerous changes, one of which would be a shift in investments away from fossil fuels and into renewable energy.

Two university student organisations - Students Taking Action for NUS to Divest (Stand) and Fossil Free Yale-NUS - have jointly launched a petition calling for the National University of Singapore (NUS) to divest its endowment funds from fossil fuel companies. There are more than 500 signatures, and growing.\

This means NUS would stop investing in fossil-fuel companies (those dealing in coal, oil and natural gas) and commit to not doing so in the future. It also means reinvesting the money into companies that are more ethical and sustainable.

Divestment is one of the most effective tools that institutions can harness to take society into a more sustainable future, because they hold great capital and social power.

By divesting from fossil-fuel companies, institutions redirect capital away from such companies, signalling that it is time to change their way of doing business. By doing so, institutions also question how socially acceptable and ethical such companies are.

While some fossil-fuel companies have given verbal commitments to change, their investment in renewable energy research remains a small fraction of their overall investments. Some oil giants, in fact, have known about the consequences of using fossil fuels since the 1980s but chose not to reveal this information or switch to renewables, and even worked to suppress climate action.

Using divestment to effect social change is not new.

From the 1960s to the 1980s, when apartheid was happening in South Africa, there was a huge movement in the United States for corporations and universities to divest from South African companies and boycott South African goods.

This generated negative publicity for these companies and added weight to the sanctions that were being imposed on the country then, leading to a weakening of the South African currency. The divestment movement is often seen as a major factor in stopping apartheid.

Divestment also makes financial sense. Climate change has exponentially increased the risk of backing coal, oil and gas, so investors should put their money elsewhere for the sake of both the planet and their own fortunes.

Limiting climate change to acceptable levels would require the world to keep a large proportion of existing fossil-fuel reserves in the ground. The assets of fossil-fuel companies, if they do not make major changes, could become stranded due to new government regulations that limit the use of fossil fuels such as carbon pricing, a change in demand brought about by a shift towards renewable energy, or even legal action. This makes it riskier to invest in them.

The fossil-fuel divestment movement began on college campuses about six years ago and has gained momentum since. Globally, about 1,000 groups and bodies have made commitments to go fossil free, with over US$6 trillion (S$8.3 trillion) in assets under management committing to get out of the most polluting fuels, according to reports.

This list ranges from cities such as New York to religious institutions such as the World Council of Churches. Over a hundred educational institutions, including Oxbridge, SOAS University of London and Stanford University, have also made commitments to divest from fossil fuel. It is in this context that Stand and Fossil Free Yale-NUS are calling for NUS to do the same.

Sustainability is a core value of NUS. It strongly supports environmentally responsible and sustainable efforts, continues to incorporate sustainable design and solutions in its campus planning, and places substantial emphasis on integrated sustainability solutions in its research, the university says.

NUS also points out that it adopts a responsible investment strategy and that its focus is on ensuring that these investments generate income that will support financial aid, education and research efforts for the benefit of its students.

Currently, a small percentage of the university's $4 billion endowment fund is still invested in fossil fuels. Divestment should therefore be in line with the university's values and goals. Divestment is an opportunity to look towards innovative and sustainable alternatives for a clean and green future. Individuals should call on their organisations and institutions to make changes. Let us not sit back and allow the choices to be made for us by rising sea levels, droughts, floods and food and water shortages.

• Melody Tay, 23, is a graduating student at Yale-NUS College, majoring in environmental studies with a focus on environmental humanities. Aidan Mock, also 23, is a third-year student at Yale-NUS College, majoring in environmental studies with a focus on marine ecology. Both are members of the Fossil Free Yale-NUS movement and have organised several events to raise awareness among the student body about divestment.