2. Why is climate change a problem?
Relatively small changes in the planet’s average temperature can lead to big changes in local and regional climate, creating risks to public health and safety, water resources, agriculture, infrastructure, and ecosystems. Climate change already has a serious impact on the world we live in today.
Every continent has warmed substantially since the 1950s. On average, there are more hot days, and the hot days are hotter. Heat waves have become longer and more frequent around the world over the past 50 years. This creates perfect conditions for extreme wildfire seasons around the globe.
Snow packs are melting earlier, leaving less water available during the heat of the summer. In some areas, this leads to reduced amounts of available freshwater, affecting major cities with droughts. Melting of sea ice and glaciers is also raising the global sea level.
Precipitation patterns are also changing. Air can hold more moisture as it warms. As a result, storms and floods are getting stronger and more frequent. This has a major impact on crops, some foods are becoming less nutritious. Increased atmospheric CO2 speeds up photosynthesis, the process that helps plants transform sunlight to food. While this makes plants grow faster, in doing so, they pack in more carbohydrates like glucose at the expense of other essential nutrients.
Many land and marine species have had to shift their geographic ranges in response to warmer temperatures. While some species may adapt to rapidly changing the land, freshwater, and marine habitats, others will suffer population declines, collapse and even extinctions.
Humans will suffer when some ecosystems no longer provide the services (food, coastal defense, clean water, etc.) we depend on. A major concern with the current episode of warming is that it is happening so rapidly that humans and nature might have insufficient time to adapt. Entire ecosystems, communities, and even countries are at great risk. Much of the human population lives in coastal areas that will be inundated by higher seas and larger storms, with property losses that will total billions of dollars in this century. Climate change is already prompting an increase in migration, with people being forced to leave their homes because of drought, flooding, and other climate-related disasters.
The Earth’s future climate will depend on whether we manage to slow or even reduce greenhouse gas emissions, but warming is likely to continue.