既然全球变暖，北半球为何如此“大寒”

Group 1 - The World Meteorological Organization confirmed that 2025 is likely to be one of the hottest years on record, continuing the trend of rising global temperatures [1][3] - The northern hemisphere is experiencing extreme weather conditions, including heavy snowfall in Russia's Kamchatka Peninsula, winter storms in the northeastern United States, and cold waves in Europe and Japan [1][2] - The extreme cold and snowfall in various regions are attributed to multiple factors, including the abnormal activity of the polar vortex and the southward movement of cold air [2][3] Group 2 - In the United States, states like Pennsylvania, New York, and New Jersey are facing widespread snowfall and extreme low temperatures, leading to flight delays and traffic disruptions [2] - Japan is also preparing for significant snowfall, with warnings issued for over five days of heavy snow in the northern and western regions [2] - Experts suggest that the relationship between global warming and extreme cold weather is complex, with changes in atmospheric circulation potentially allowing cold air to extend further south [3]