As people around the globe observe Earth Day today, world leaders are making history at the United Nations in New York. Over 100 countries will sign the Paris Agreement on climate change, representing their commitment to join it formally. This marks a turning point in the story of our planet and may set a record for the largest number of signers to an international agreement in a single day. Moreover, last month, President Obama announced with President Xi Jinping that our two countries will sign the Paris Agreement today and formally join this year. We are confident other countries will do so too, with the intention of bringing this historic and ambitious agreement into force as quickly as possible.

A greener future is already in sight. Leaders of countries and cities are adapting and innovating away from fossil fuels and business owners are investing in a clean energy economy. The United States is moving forward in its commitment to cut greenhouse gas emissions 26-28 percent from 2005 levels by 2025. We are doing this through the strongest fuel economy standards in our history, through our twenty-fold increase in solar generation since 2009, and through proposed rules on everything from energy conservation standards for appliances to reduction in emissions of methane-rich gas from municipal solid waste landfills.

My home state, New Jersey, has undertaken ambitious programmes tackling climate change and promoting renewable energy. The New Jersey Department of Environmental Protection has introduced the Sustainable Jersey programme to aid cities and towns in going green, saving money, and taking the steps necessary to ensure long-term quality of life.  Sustainable Jersey provides guidance and financial incentives in support of the programme. The New Jersey Board of Public Utilities' Clean Energy Programme encourages homeowners, businesses, and municipalities to incorporate clean energy into their lives. The Clean Energy Programme has received the 2016 Sustained Excellence Award from the United States Environmental Protection Agency for 15 years of success in promoting clean energy use.

While we are taking significant climate action domestically, the United States is also focused on international cooperation to address this global challenge. Our $500 million contribution last month to the Green Climate Fund (GCF) – the first tranche of the $3 billion U.S. pledge to the GCF – will help developing countries reduce carbon emissions and prepare for climate impacts, while also advancing our commitment to achieving the Sustainable Development Goals – another major landmark agreement the world came together around last year.

One of the most successful environmental agreements of all time is the Montreal Protocol, which is phasing out ozone depleting substances globally. It set the ozone layer on a path to recovery and prevented tens of millions of cases of skin cancer among other health, environmental, and economic benefits. Hydrofluorocarbons (HFCs) – which replace many of the ozone-depleting substances – do not harm the ozone layer, but they are greenhouse gases that in some cases can be thousands of times more potent than carbon dioxide. The United States is working with partners to adopt an HFC phase-down amendment to the Montreal Protocol this year that could avoid half a degree Celsius of warming by the end of the century. 

We also need international cooperation to change how we transport ourselves and goods.  The aviation sector represents two percent of the world's total greenhouse gas emissions. The International Civil Aviation Organisation is aiming to achieve carbon neutral growth for international aviation by 2020. The United States is committed to reaching an agreement on a global market-based measure that will help move the airline sector toward this ambitious goal.

Bangladesh, located at the confluence of the Ganges, the Brahmaputra, and the Meghna rivers, is uniquely vulnerable to climate change. The 600 kilometre coastal zone faces considerable challenges: flooding, erosion, rising sea levels, and cyclonic storm surges.  Bangladesh has risen to this challenge. From the establishment of the Bangladesh Climate Change Strategy and Action Plan of 2009 and Climate Change Trust Fund to the continued dedication of over six percent of the annual budget to climate change adaptation, Bangladesh has been on the leading edge of environmental policy. For all of these reasons, Prime Minister Sheikh Hasina was awarded the United Nations' Champion of the Earth award for Policy Leadership last September.  

This Earth Day – with the signing of the Paris Agreement – is truly a cause for hope. It is also a reminder of our shared commitment to combat climate change. We must all seize upon the momentum from Paris to build a clean energy future for ourselves and our children and grandchildren.  

The writer is the U.S. Ambassador to Bangladesh.