Climate change is primarily caused by human activities, especially the burning of fossil fuels, deforestation, and industrial practices that increase greenhouse gas emissions. These gases trap heat in the atmosphere, leading to global warming. The effects on ecosystems include rising sea levels, altered weather patterns, loss of biodiversity, and shifts in habitats. Species may struggle to adapt, leading to extinction or migration, while ecosystems like coral reefs and wetlands are particularly vulnerable. Mitigating climate change requires reducing emissions, transitioning to renewable energy, and implementing conservation measures.