A Warming World: The Impacts of Climate Change

Newtok is a small village on the coast of Alaska, USA. It sits on permafrost — ground that used to stay frozen all year round. But the permafrost is thawing, and the coastline is eroding by up to nine metres every year. The village is sinking into the mud. By 2023, most of its 300 residents had begun relocating to a new site called Mertarvik. Newtok may become uninhabitable within years. Think about that: an entire community forced to move because of changes to the climate.

Climate change refers to long-term shifts in global temperatures and weather patterns, driven mainly by the build-up of greenhouse gases — such as carbon dioxide and methane — in the atmosphere. These gases trap heat from the Sun, causing Earth's average temperature to rise. Since the mid-19th century, average global temperatures have risen by approximately 1.2 °C. That may sound small, but it is enough to trigger wide-ranging impacts across the planet. **Rising sea levels** are one of the most visible impacts. As the ocean warms, seawater expands. Glaciers and ice sheets in Greenland and Antarctica also melt, adding more water to the ocean. Global sea levels rose by about 20 cm during the 20th century and are rising faster today. Low-lying nations such as Bangladesh and small island states like Tuvalu in the Pacific Ocean face devastating flooding and may lose significant land area by the end of this century. **Extreme weather events** are becoming more frequent and more intense. A warmer atmosphere holds more moisture, which fuels stronger hurricanes and heavier rainfall events. At the same time, higher temperatures increase evaporation from soil, making droughts more severe in already dry regions such as sub-Saharan Africa and southern Spain. **Ecosystem disruption** occurs when habitats change faster than species can adapt. Coral reefs — among the most biodiverse ecosystems on Earth — suffer bleaching when ocean temperatures rise even slightly. The Great Barrier Reef off the coast of Australia has experienced multiple mass bleaching events since 1998. Species migration patterns are also shifting: many plants are flowering earlier, and some animals are moving poleward or to higher altitudes to find suitable temperatures. **Food and water security** are under pressure too. Glaciers in the Himalayas and the Andes supply meltwater to rivers that millions of people in South and Central Asia depend on for drinking water and irrigation. As glaciers shrink, seasonal water supplies become unreliable. Changing rainfall patterns reduce crop yields in some regions while flooding agricultural land in others. **Human displacement** — sometimes called climate migration — results when people can no longer live safely or sustainably in their home regions. The Internal Displacement Monitoring Centre estimated that weather-related disasters displaced over 20 million people internally in 2020 alone. Vulnerability is not equal: poorer nations with fewer resources to adapt tend to suffer the worst consequences, even though they have contributed the least to greenhouse gas emissions. This disparity is called **climate injustice**.