Climate change and the effects.
Atmospheric carbon dioxide levels reached an all-time high in 2020, reaching 417 parts per million in May. The last time carbon dioxide levels exceeded 400 ppm was about 4 million years ago, during the Pliocene epoch, when global temperatures rose by 2-4°C, and sea levels were 10-25 meters (33-82 feet) higher than before.
“If we continue to monitor the worst-case scenario, CO2 levels will be 800 parts per million by this century. We haven’t had it for 55 million years.
Then there was no ice on the planet, and it was 12 ° C warmer, says Siegert. The last decade has been the hottest on record. the hottest year on record, while globally, 2020 was the most desirable than 2016.
Record temperatures, including in 2016, usually coincide with the El Niño event (a large swath of warm water that forms in the Pacific Ocean every few years), leading to a large-scale rise in Pacific surface temperatures. But 2020 was unusual because the world experienced a La Niña event (the opposite of El Niño, with a more relaxed band of water forming). In other words, if La Niña had not lowered global temperatures, 2020 would have been even warmer.
Nowhere is the temperature rise felt like it is in the Arctic. In June 2020, temperatures in Eastern Siberia reached 38°C, the highest temperature ever recorded above the Arctic Circle.
The heatwave accelerated sea ice melt in the East Siberian and Laptev Seas and delayed expected Arctic frosts by nearly two months. “You’ve definitely seen the effects of these warm temperatures,” said Julien Stroeve, a polar scientist at University College London. On the Eurasian side of the Arctic Circle, the ice does not freeze until late October, very late. In the summer of 2020, sea ice extent was the second-lowest on record, as was sea ice extent, which includes a more significant number of areas of the ocean where at least 15 per cent of ice is present.
Ice loss is not only a symptom of climate change but also a determining factor. The gleaming whiteness of the sea ice plays a vital role in reflecting the sun’s heat back into space, like a reflective jacket. But the Arctic is warming twice as fast as the rest of the world, and as the ice gets thinner during the hot summer months, we lose its reflective protection. Instead, large areas of open dark water absorb more heat, further fueling global warming.
Multi-year ice is thicker and more reflective than the thin, dark seasonal ice that increasingly replaces it. From 1979 to 2018, the percentage of Arctic sea ice present for at least five years fell from 30% to 2%, according to the IPCC. “White ice reflects a lot of solar energy and helps slow the rate of global warming,” said polar explorer Michael Meredith of the British Antarctic Survey.
“We are accelerating global warming by reducing Arctic sea ice.” The loss of ice is already thought to be disrupting weather patterns around the world. According to the Grantham Institute, it is possible, though not conclusively proven, that Arctic conditions in 2018 caused the 2018 European winter storm “The Beast from the East” by altering the jet stream, a strong air current in Europe’s atmosphere. “Temperature differences between the equator and the poles govern many of our large-scale weather systems, including the jet stream,” Stroeve says.
And since the Arctic is warming faster than the lower latitudes, the jet stream is weakening. If one part of the climate system changes, the rest of the system will respond,” Stroeve says. Across the Northern Hemisphere, permafrost, land that remains frozen year-round for two or more years, is warming rapidly. The air temperature reaches 38°. With (100°F) in Siberia in the summer of 2020, ground temperatures in different parts of the Arctic Circle reached a record 45°C (113°F), accelerating the melting of permafrost in the region. ) are in decline.
Permafrost contains large amounts of greenhouse gases, including carbon dioxide and methane, released into the atmosphere during thawing. The soil of the permafrost spans about 23 million square kilometres (8.9 million square miles) across Siberia, Greenland, Canada and the Arctic, and its atmosphere contains twice as much carbon at nearly 1.6 trillion tons. Most carbon is stored in the form of methane, a potent greenhouse gas that is 84 times more responsible for global warming than carbon dioxide. “Permafrost keeps carbon out of the atmosphere, which helps us greatly,” Meredith said.
Melting permafrost also damages existing infrastructure and destroys the livelihoods of indigenous communities who use the frozen land for transportation and hunting. This has contributed to the collapse of a massive fuel tank in the Russian Arctic in May, spilling 20,000 tons of diesel fuel into the river.
Since 1990, the world has lost 178 million hectares (690,000 square miles) of the forest, an area the size of Libya. The pace of deforestation has slowed over the past three decades, but experts say that’s not enough given the critical role forests play in curbing global warming. The annual rate of deforestation was 10 million hectares (39,000 square miles, or roughly the size of Iceland) in 2015-2020, compared with 12 million hectares (46,000 square miles) in the previous five years.
“Global forest areas continue to shrink,” says Bonnie Waring, senior lecturer at the Grantham Institute, noting significant regional differences. “We are losing a lot of tropical forests in South America, and Africa [and] are reclaiming temperate forests through tree planting or natural regeneration in Europe and Asia.” Brazil, the Democratic Republic of the Congo and Indonesia are the countries that are losing forest cover the fastest. In 2020, the clearing of the Amazon rainforest hit a 12-year high.