As nations look to the crucial Climate Summit to be hosted by U.N. Secretary General Antonio Guterres in September, leaders need to know that buildings and construction contribute close to 40 percent of global emissions while exacerbating the air pollution that causes some seven million deaths annually.
Today the way our homes and offices are built and operated is one of -- if not the -- biggest sources of climate-wrecking emissions: a fact we overlook at our peril.
Progress is happening. Super-efficient lighting, such as LEDs, is becoming cheaper and more commonplace and the rapid growth in renewable energy worldwide is helping more buildings run with a lower carbon footprint.
But without urgent action these important gains will be overwhelmed by building booms mainly in emerging economies.
Every week, an area of floor space the size of Paris is constructed, often locking in high emission infrastructure that will be with us for decades to come. Over 60 percent of the land needed for urban development by 2030 has yet to be built upon.
If this trend continues unabated through to 2050, a key date for achieving the Paris Climate Change Agreement, we will have slammed the door and thrown away the key to a climate-secure future, let alone the promise of a better world via the Sustainable Development Goals.
We understand it is a challenge. Many common construction materials and practices -- like cement and steel production -- are energy hungry and depend on fossil fuels.
The sector is fragmented across an array of businesses and workers -- from architects and designers to engineers, building and energy companies, appliance suppliers and materials manufacturers. These long supply chains crisscross the globe.
Energy use for cooling has already increased 25 percent since 2010. There are now more than 1.6 billion air-conditioning units globally and billions more soon to be installed.
These challenges sparked governments, cities, the private sector and future-looking organizations to forge the Global Alliance for Buildings and Construction (GlobalABC) in 2015.
Its new "Global Assessment Report" makes sobering reading but also shines a light on actions happening in countries and communities everywhere that are paving the way "Towards a Zero-Emission, Efficient and Resilient Buildings and Construction Sector."
For example, in the European Union, the Energy Performance of Buildings Directive entered into force in July last year backed by measures to meet its 2050 aim of fully decarbonized buildings.
Already 15 businesses and organizations, 22 cities and five states and regions have signed up to the Net Zero Carbon Buildings Commitment of the World Green Building Council.
Smart procurement is driving the market in India for low cost LEDs and more efficient air conditioners, and Mexico's EcoCasa program provides incentives to build energy-efficient "passive homes."
The Alliance's report outlines how ambition can be taken to the next level so that buildings and construction can cut their carbon footprint by 30 percent by 2030, pinpointing widespread, smarter building codes as one key pathway.
Over the next few years nations are poised to raise their national climate action plans -- known as Nationally-Determined Contributions (NDCs) -- to get better on track with the Paris Agreement's goals.
As leaders look to the U.N. Climate Summit on Sept. 23 as a springboard for higher ambition NDCs, we urge them to put buildings and construction front and center in the push toward having global emissions peak by 2020 and setting the stage for a carbon neutral world by mid-century.
(Joyce Msuya is acting executive director of the U.N. Environment Program; Cristina Gamboa, CEO of World Green Building Council, and Gino Van Begin, secretary general of the ICLEI-Local Governments for Sustainability, also contributed to the opinion piece.)