Net-Zero Cities: Goals and Solutions

Green

April 8, 2020, 5:19 pm

By: Dr Samar Hamad

The rapid increase in global temperature has received great attention owing to its relation to climate change. According to the National Aeronautics and Space Administration (NASA), the average temperature of Earth’s surface has significantly increased by 0.6 to 0.9°C over the past century with higher rates in the past 50 years. The National Oceanic and Atmospheric Administration (NOAA) indicates that the average rate of increase has reached 0.07°C per decade since 1981. This temperature rise can be attributed to the increasing amount of greenhouse gases (GHGs) released to the atmosphere. The growing urgency to stabilize the global temperature is the driving force behind the net-zero movement, as a direct reaction to mitigate climate change.

What’s Net-Zero Emissions?

Countries, states, and cities around the world have committed to the targets set by the 2016 Paris Agreement and 2019 Climate Action Summit to achieve net-zero carbon emissions by 2050. This is a global vision to create net-zero carbon neutral communities by seeking a wide range of sustainability-related goals. The central aim of the net-zero movement is to mitigate the impact of climate change by limiting the global temperature rise to 1.5°C above pre-industrial levels to avoid irreversible damages to Earth. The term net-zero emissions implies removing “human caused” GHG emissions such as emission from burning fossil fuels (also known as carbon removal). The remaining carbon emissions must also be balanced, for instance by restoring forests or using the “direct air capture and storage (DACS) technology”.

How to Achieve Net-Zero Emissions?

A variety of solutions can be implemented to develop more sustainable economies, cut GHG emissions, and ultimately achieve net-zero goals. National and local governments are adopting policies in an effort to regulate the major sectors that have always been regarded as part of the climate change problem. These efforts aim not only to minimise the negative impact of these sectors but also involve them in the solution. The sectors that need to prioritize cutting their carbon emissions are:

• Buildings

Achieving net-zero buildings is challenging owing to their long lifespan and slow turnover. Many cities are implementing mandatory “minimum energy efficiency codes” to regulate the building industry. While others are introducing “net metering schemes” to promote installing onsite renewable energy solutions and engaging “non-utility actors” in green power purchasing agreements. Furthermore, electrifying new and existing buildings is key to increase the reliance of the building sector on renewables and realize significant reduction in the amount of GHGs released by buildings. Thus, an integrated design approach to achieve healthier, more energy efficient buildings with lower loads is the most appropriate pathway to net-zero buildings. This is an optimal design approach that incorporates passive design techniques with less glazing area to lower the building loads combined with advanced mechanical systems coupled with optimal controls to optimize buildings’ operation and maintenance, in addition to integrating renewable energy solutions (such as solar arrays) for lower carbon future.

• Transportation and Mobility

Many cities are pursuing low-carbon transportation modes and mobility options (such as public transit, walking, biking, etc.) to minimise their reliance on fossil fuels for transportation and lower their overall carbon emissions. Fuel efficiency, “mode-shift”, and “fuel-switching” measures are also crucial to eliminate transportation-related emissions. Recently, electric vehicles have emerged as low-emission transportation option. Cities around the world are installing electric cars charging stations that run on renewable energy (such as solar-powered charging stations) to further lower their emissions.

• Waste

Limiting the amount of waste disposal to landfills and increasing the recovery rate of recyclable/compostable materials are central to realizing significant reduction in carbon emissions. However, lowering the consumption of goods and services is the key to reduce the amount of waste generated in the first place. In order to achieve their zero waste goals, cities are planning to reduce, reuse, and recycle/compost discarded materials to eliminate waste disposal to landfills.

• Energy

Many cities worldwide are committed to “decarbonise” their electric grids in an effort to cut their carbon emissions. This can be achieved by eliminating the use of fossil fuels in power generation. They are increasingly relying on electricity generated from emissions-free renewable energy sources such as hydropower, wind, and solar energy sources. The energy supply from such clean resources must also be coupled with smart distribution/management systems and energy storage solutions for efficient grid optimization.

In addition to the four major sectors discussed above, business and industrial corporations are also contributing to the net-zero efforts. They are increasingly relying on renewable energy sources for onsite electricity generation and continuously adjusting their supply chains to lower carbon emissions. Adopting a more sustainable approach to production and consumption is vital to achieve such ambitious carbon-reduction goals.

Overall, the net-zero targets must be incorporated into the long-term planning strategies of cities, especially those considered as major emitters (cities located in USA, Europe, China, etc.). In order to further accelerate their climate change mitigation efforts, those cities also need to use globally accepted protocols to closely track and report their emissions and measure the progress toward achieving their net-zero goals.

More information is available at:

The National Aeronautics and Space Administration (NASA) website: https://earthobservatory.nasa.gov/

National Centers for Environmental Information – The National Oceanic and Atmospheric Administration (NOAA): https://www.ncei.noaa.gov/