Global warming is caused by heat-trapping gases like carbon dioxide and methane that are emitted through human activities like burning fossil fuels and deforestation. These gases trap heat in the atmosphere and cause Earth's surface temperature to rise, disrupting climate patterns. Effects of global warming include extreme heat, rising sea levels, more intense storms, droughts, and declining crop yields. International efforts to address global warming include the UN Framework Convention on Climate Change and its Kyoto Protocol that aim to reduce greenhouse gas emissions. Individual actions like conserving energy and planting trees can also help mitigate the problem.