Global warming is the long-term heating of Earth’s surface observed since the pre-industrial period (between 1850 and 1900) due to human activities, primarily fossil fuel burning, which increases heat-trapping greenhouse gas levels in Earth’s atmosphere. It occurs when carbon dioxide (CO2) and other air pollutants collect in the atmosphere and absorb sunlight and solar radiation that have bounced off the earth’s surface. Normally this radiation would escape into space, but these pollutants, which can last for years to centuries in the atmosphere, trap the heat and cause the planet to get hotter. Climate change is a long-term change in the average weather patterns that have come to define Earths local, regional, and global climates. While many people think of global warming and climate change as synonyms, scientists use “climate change” when describing the complex shifts now affecting our planet’s weather and climate systems—in part because some areas actually get cooler in the short term. The impacts of global warming are being felt everywhere, including extreme heat waves that have caused tens of thousands of deaths around the world in recent years, and the loss of nearly four trillion metric tons of ice in Antarctica since the 1990s. The rate of loss could speed up if we keep burning fossil fuels at our current pace, causing sea levels to rise several meters in the next 50 to 150 years and wreaking havoc on coastal communities worldwide.