In an era where global temperatures are on the rise, the United Nations headquarters in New York has turned to an innovative and eco-friendly solution to keep its premises cool. Utilizing the East River's waters, the UN employs a water-based cooling system that stands as a testament to sustainable practices. This system, in place since the 1950s, has been modernized to ensure efficiency, showcasing how traditional methods can be adapted to meet contemporary environmental challenges.

The cooling mechanism at the UN headquarters is a prime example of energy efficiency. By drawing water from the East River, a saltwater estuary that remains significantly cooler than the summer air, the system reduces energy consumption compared to conventional air conditioning. With the capacity to circulate up to 26,000 liters of water per minute through fiberglass pipes, the system not only cools the building effectively but also minimizes its environmental footprint.

David Lindsay, the head of the cooling system, highlights the importance of the system's design, which includes two independent loops to prevent contamination of the river water. This careful consideration ensures that the water returned to the East River, though at a higher temperature, does not harm the aquatic ecosystem. Such details underscore the UN's commitment to environmental stewardship and sustainable development.

The success of the water-based cooling system at the UN headquarters serves as a model for other large organizations seeking sustainable alternatives to traditional cooling methods. With similar systems in place at the UN's Geneva office, which uses Lake Geneva's waters, the potential for water-based cooling solutions is evident. As the planet continues to warm, the need for innovative and sustainable cooling technologies becomes increasingly urgent, making the UN's approach a valuable case study in environmental responsibility.

Paris has recently been recognized as the most cycling-friendly city for children in Europe, surpassing traditional leaders like Amsterdam and Copenhagen. This achievement is attributed to significant investments in cycling infrastructure, including the creation of 180km of cycling lanes and preparations for the 2024 Paris Olympics. The city's transformation over the past decade highlights a shift towards more sustainable and child-friendly urban mobility.

The Clean Cities Campaign report, which analyzed 36 European cities, placed Paris at the top due to its extensive network of protected cycling lanes and the implementation of a 30km/h speed limit across the city. These measures have not only made cycling safer for children but have also contributed to a decrease in car usage, with bicycles now accounting for more than 11 percent of journeys in the city.

Other cities such as Brussels, Lyon, and Helsinki also made notable progress, securing spots in the top ten. The report emphasizes the importance of child mobility in urban areas, where over 70 percent of the EU population resides. It also points out that children, especially girls, are becoming less active and free to move around cities, underscoring the need for safe cycling infrastructure.

The success of Paris and other cities in improving their cycling infrastructure demonstrates that meaningful change can be achieved within a relatively short period. This serves as a model for other urban areas aiming to enhance their cycling networks and promote healthier, more sustainable modes of transportation for future generations.