Last year was a strong and painful reminder of the ongoing and accelerating climate change crisis. Indeed, 2019 ended up as the second-warmest year on record; wildfires destroyed huge areas of the Amazon and Australian forests; last July, European cities witnessed temperatures close to 50 degrees Celsius; and many regions around the world experienced unprecedented floods. Environmental activists and nongovernmental organizations redoubled their efforts to press governments to implement more effective and stringent policies, but this mostly led to sneers and dismissals, such as “prophets of doom,” or “waste of time.” COP25 (the UN Climate Change Conference) that was held in Madrid in December and the World Economic Forum (the yearly gathering in Davos, Switzerland, of world leaders and intelligentsia) that was held just last week both failed to make any progress on the climate crisis. In the meantime, however, cities have stepped up their efforts to lessen the unfolding disaster. First, a good dozen major cities have started to implement car-free or at least car-restriction policies to reduce pollution and carbon dioxide production, not to mention accidents, while improving air quality and decreasing greenhouse gas emissions. For example, Madrid has banned older cars from its city center and Paris has made the first Sunday of every month free of cars. More ambitious are complete programs that have been set up by cities like Copenhagen to become carbon-neutral by 2025 or so. Actually, the Danish capital has been implementing a full plan for the past 15 years. It includes thousands of square meters of solar panels, usage of renewable energy for the city’s heating, reducing car transportation in the city by 25 percent or more (pushing the public to use bikes and/or public transport), transforming buildings, and more. So far 42 percent of carbon dioxide emissions have been cut, 66 percent of all trips in the city are now done by zero-carbon or minimal-emission means, and 51 percent of heat and power is produced by renewable energies. All this, observers insist, without upsetting the city’s economic growth. City mayors and councils around the world have realized that, while they cannot solve the climate change problem on their own, they can do a lot. Indeed, 55 percent of humanity today lives in cities and, by 2050, this will increase to 70 percent. Roughly two-thirds of all greenhouse gas emissions come from cities. Amazingly, with programs such as Copenhagen’s, 90 percent of urban emissions could be cut, greatly helping the world achieve the goals of the major COP21 Paris conference, where a plan was put in motion to keep the global temperature increase to less than 2 C. But besides constraints on inner-city transportation and heating/cooling by renewable energies, what could and should cities be doing to help address the problem? First, they can impose new regulations that make buildings (new ones and, where possible, old ones) greener, such as using solar panels as extensively as possible, and being more energy efficient. A number of cities around the world have started such programs — 800 buildings in Mexico City, to give just one example. Secondly, some cities are applying new standards for the materials that are used everywhere — in airports, vehicles, pavements, parks, stadiums, railroads, etc. — to both improve energy efficiency and minimize the production of greenhouse gases. Yet cities are limited in what they can achieve. Green energy can only become a reality if governments build large solar plants, wind turbines, and nuclear reactors that bring in zero-carbon energy. And that is a major strategic program that governments need to adopt and implement. A word about nuclear energy in this regard. After Chernobyl (34 years ago) and Fukushima (nine years ago), atomic energy acquired a very bad reputation and countries like Germany decided to phase it out. The public widely perceives it as dangerous, even though the only deaths in Fukushima were due to the earthquake and the tsunami, not the reactor accident. In Chernobyl, it’s a more complicated story, but much less gloomy than people tend to think. Still, even if one believes that current reactors are not safe, there are important, revolutionary works that are ushering in new, very safe reactors. And, most importantly, nuclear reactors (today’s and tomorrow’s) are essentially carbon-free. Bill Gates, who has invested in a research program to develop such safe reactors (which automatically shutdown upon any sudden problem), has said: “Nuclear is ideal for dealing with climate change.” I should note that the UAE’s nuclear program is nearing fruition, with the first unit slated to reach full power this year. We will undoubtedly be discussing this nuclear path in the years to come. Whether nuclear reactors will play an important role in the reduction of global warming, only the future will tell. But, either way, cities and governments will need to implement new solutions and citizens will have to adopt new ways of living in the world if we want our lives and those of our children not to be hellish in the future. Nidhal Guessoum is a professor of physics and astronomy at the American University of Sharjah, UAE. Twitter: @NidhalGuessoum Disclaimer: Views expressed by writers in this section are their own and do not necessarily reflect Arab News" point-of-view