— Ch. 1 · Global Temperature Trends —
Effects of climate change.
~5 min read · Ch. 1 of 7
The 20th century was the hottest in nearly 2,000 years. Scientists have studied tree rings and ice cores to understand this rapid change. Global surface temperatures have risen by about 1.1 degrees Celsius since pre-industrial times. Land areas have warmed at twice the rate of ocean surfaces. Night-time temperatures have increased faster than daytime temperatures. The Arctic has warmed more than any other region on Earth. This uneven warming creates intense heat waves over land. These changes would stabilize if greenhouse gas emissions were brought under control. However, current policies suggest a rise of 2.7 degrees Celsius by 2100. Even if all countries meet their net-zero targets, temperatures will still rise by around 1.9 degrees. The gap between national plans and actual actions remains wide.
Extreme Weather Intensification
Heatwaves over land have become more frequent and intense since the 1950s. A heatwave that occurred once every ten years before global warming now happens 2.8 times as often. Marine heatwaves are twice as likely today compared to 1980. Higher temperatures increase evaporation and atmospheric moisture content. Water vapor acts as a greenhouse gas, creating a self-reinforcing feedback loop. This excess water gets caught in storms, making them larger and longer-lasting. Heavy rainfall events lead to increased flooding risks. Conversely, extra drying worsens natural dry spells and droughts. In some tropical regions, there is less rain due to global warming. Central America, the Amazon, and parts of Africa face worsening drought conditions. Wildfires spread rapidly when vegetation and soils dry out. The fire season lengthens, particularly where snow disappears. Climate models do not yet fully reflect this feedback mechanism.