Read the passage below and summarize it in one sentence:
Climate change represents one of the most pressing challenges of the 21st century, affecting ecosystems, economies, and societies worldwide. The scientific consensus is clear: human activities, particularly the burning of fossil fuels and deforestation, have significantly increased greenhouse gas concentrations in the atmosphere, leading to rising global temperatures. This warming has resulted in melting ice caps, rising sea levels, extreme weather events, and shifts in precipitation patterns. To mitigate these effects, nations around the world have committed to reducing carbon emissions through international agreements like the Paris Accord. However, transitioning to renewable energy sources requires substantial investment in new technologies, infrastructure, and changes in both industrial practices and individual behaviors. The urgency of this transition is underscored by projections that without immediate action, the consequences could become irreversible, threatening food security, water resources, and biodiversity on a global scale.