A United Nations chief has called on global leaders to show the "same determination" exerted to tackle the coronavirus crisis to address ongoing concerns over climate change. On the 50th Earth Day - an annual event to highlight the importance of protecting the planet - the world is facing unprecedented challenges. Strict measures imposed to stem the spread of Covid-19 have forced a third of the world's population into lockdown. This has offered a sliver of a silver lining for the environment, as skies, seas and rivers have become cleaner and quieter and highways have emptied, leading to a dramatic drop in air pollution across the globe. However, the United Nations' World Meteorological Organisation (WMO) said the improvements were only temporary and long-term plans still needed to be developed to address the issue. Organisers of Earth Day said the many events planned to promote this year’s theme of climate change would instead take place online. “Covid-19 may result in a temporary reduction in greenhouse gas emissions, but it is not a substitute for sustained climate action,” said the organisation. Its secretary general, Petteri Taalas, said Covid-19 caused a severe international health and economic crisis, but failure to tackle climate change may threaten human well-being, ecosystems and economies “for centuries”. UAE pupil and environmental campaigner Sainath Manikandan said the pandemic has resulted in positive benefits that the world now needs to build on. "Because of the global shutdown, we have seen carbon emissions dropping," said Sainath, 11, an active member of Emirates Environmental Group who <a href="https://www.thenational.ae/uae/environment/abu-dhabi-pupil-invents-marine-robot-to-chew-through-the-world-s-oceans-plastic-problem-1.856437">developed a robot to devour waste clogging the oceans</a>. He is taking part in two digital Earth Day events in the UAE, including one hosted by his school, Gems United Indian School, in Abu Dhabi and another he organised himself that uses art to promote awareness of climate change. “We have also realised that a few of us can actually work from home, which greatly reduces carbon emissions," he said. "In short, all governments and leaders need to take these factors into account and focus on creating new environmental laws and policies to encourage a sustainable environment by reducing the pollution or similar activities and save our earth.” The WMO said a new global temperature record is likely to occur in the next five years if nothing was done to reverse climate change. It has warned it would make it more difficult to tackle weather, climate and water-related hazards, which are becoming more acute because of climate change. Extreme weather events, which have increased, would not go away because of the coronavirus, said Mr Taalas. “On the contrary, the pandemic exacerbates the challenge of evacuating people and keeping them safe from tropical cyclones, as we saw with category five strength Harold in the South Pacific. “And there is a risk that over stretched health systems may not be able to cope with an additional burden of patients due to, for example, heatwaves,” he said. “We need to show the same determination and unity against climate change as against Covid-19. We need to act together in the interests of the health and welfare of humanity not just for the coming weeks and months, but for many generations ahead.”