climatechange

Climate change refers to long-term shifts in patterns of temperature, precipitation, and other aspects of the climate system. While natural variability plays a role, the current trend is dominated by human activities that increase the concentration of greenhouse gases in the atmosphere, notably carbon dioxide from fossil fuel combustion, methane from energy and agriculture, nitrous oxide, and fluorinated gases. These gases trap heat and alter the energy balance of the planet, leading to warming and other changes.

Evidence includes rising global average surface temperatures, warming oceans, shrinking Arctic sea ice, retreat of glaciers, and rising sea levels. The last decade has been the warmest on record, and many regions experience more frequent and intense heat waves, heavier rainfall, droughts, and stronger tropical cyclones. Attributing individual events to climate change is complex, but many recent extremes exceed what would be expected from natural variability alone.

Impacts include shifts in ecosystems and species distributions, coral reef degradation, disruptions to agriculture and food security, stress on water resources, health risks from heat and vector-borne diseases, and broader economic costs. Vulnerable communities and regions face heightened risks from extreme weather, sea level rise, and resource scarcity.

Responses encompass mitigation to reduce greenhouse gas emissions and remove CO2 from the atmosphere, through cleaner energy, energy efficiency, transport changes, land-use practices, and carbon capture and storage. Adaptation measures increase resilience, such as infrastructure upgrades, early warning systems, and water and drought management. International cooperation under agreements like the UN Framework Convention on Climate Change and the Paris Agreement seeks to align national policies, though commitments and timelines vary. Ongoing scientific research and technological innovation support these efforts.