Leanna Arcila, 7, is licked by Watson, a therapy dog with the Pawtucket police department, as she receives her COVID-19 vaccination from Dr. Eugenio Fernandez at Nathanael Greene Elementary School in Pawtucket, R.I., Tuesday, December 7, 2021. Even as the U.S. reaches a COVID-19 milestone of roughly 200 million fully-vaccinated people, infections and hospitalizations are spiking, including in highly-vaccinated pockets of the country like New England. (Photo by David Goldman/AP Photo)

A bird swoops in to deliver its food to its chick, ramming it deep into its mouth while in flight. The photos of the swallows were captured by Kelvin Leong in Hampstead Wetlands Park, Singapore in July 2023. (Photo by Kelvin Leong/Solent News & Photo Agency)

A combination photo shows some of the colourful doors seen in Rabat's Medina and Kasbah of the Udayas, September 2014. UNESCO made Rabat a World Heritage Site two years ago and media and tour operators call it a “must-see destination”. But it seems the tourist hordes have yet to find out. While visitors are getting squeezed through the better-known sites of Marrakesh and Fez, the old part of Rabat - with its beautiful Medina and Kasbah of the Udayas - remains an almost unspoiled oasis of calm. Smaller and more compact, its labyrinths of streets, passages and dead ends are a treasure trove of shapes and colours, of moments begging to be caught by the photographer's lens. (Photo by Damir Sagolj/Reuters)

This undated handout photograph released by Stony Brook University/ Louisiana State University on March 2, 2018, shows an Adélie penguin looking at a drone at breeding colony on Heroina Island, Danger Islands, Antarctica. A thriving “hotspot” of some 1.5 million Adelie penguins has been discovered on the remote Danger Islands in the east Antarctic, surprised scientists announced on March 2, 2018. (Photo by Rachael Herman/AFP Photo/Louisiana State University AND Stony Brook University)

Rapper Destiny Nicole Frasqueri, known professionally as Princess Nokia performs during the Coachella Valley Music and Arts Festival held at the Empire Polo Club in Indio, California, U.S., April 22, 2022. (Photo by Maria Alejandra Cardona/Reuters)

A Russian female military cadet marches in front of the Eternal Flame at the WWII memorial complex at Poklonnaya Hill in Moscow on February 17, 2021, during a rehearsal for the upcoming February 23's Defender of the Fatherland Day. (Photo by Alexander Nemenov/AFP Photo)

A Typhoon jet flown by Flt Lt Jim Peterson practising over RAF Coningsby in the East Lindsey district of Lincolnshire, England on September 27, 2019 producing a rainbow effect over the plane. The rainbow is made of crystalized or frozen water vapor that reflect and refract sunlight, causing the rainbow effect. (Photo by Claire Hartley/Bav Media)

The Greenland ice sheet is a vast body of ice covering 660,235 sq miles, roughly 80% of the surface of Greenland. It is the second largest ice body in the world, after the Antarctic Ice Sheet. Some scientists predict that climate change may be near a "tipping point" where the entire ice sheet will melt in about 2000 years. If the entire 2,850,000 cubic kilometres (683,751 cu mi) of ice were to melt, it would lead to a global sea level rise of 7.2 m (23.6 ft).