The climate system is a complex system, influenced by solar energy and other natural processes, but it’s also affected by changes humans make to the planet. The main change human activities have caused is the addition of greenhouse gases to the atmosphere.
Greenhouse gases like carbon dioxide, methane and nitrous oxide absorb heat from the Sun. They change the way Earth’s temperature is regulated. Some of that heat is re-radiated back to space, while other energy is trapped in the atmosphere and the ocean.
Warmer temperatures are already affecting many aspects of our lives, from the weather we experience to the food we eat and the ecosystems we live in. Even small changes can cause major problems, from the melting of ice sheets and glaciers to a rise in sea level that threatens coastal communities.
Climate is always changing, but the last few decades have seen the biggest changes since humans began pumping greenhouse gases into the air. These changes are causing the planet to warm, with average global temperatures rising by 2.2 degrees Fahrenheit (1.1 degrees Celsius) in the past century.
The warming is mainly caused by the addition of carbon dioxide to the atmosphere from burning fossil fuels, but other changes in the climate are also occurring. Some of the excess greenhouse gas emissions are being taken up by the ocean, changing its chemical composition and causing ocean acidification.
Some of this acidification is making the water more salty, which affects marine life and can damage habitats for fish, otters, seals and coral reefs. The saltwater can also make oceans more susceptible to storm surge and erosion, putting coastal areas at risk of destruction and flooding.
There are no simple solutions to climate change, but reducing greenhouse gas emissions by switching from fossil fuels to clean, renewable sources of energy can help keep global temperature increases below 1.5 degrees Celsius, the point at which catastrophic impacts become unavoidable. Fossil fuel production must decline by about six per cent a year between 2020 and 2030 to stay below that target.
People are starting to worry about climate change more and more, especially in the United States. A third of women say they will reduce their expected family size because of the threat.
Scientists are learning more and more about the effects of climate change, both on the planet and on the people who live here. These impacts can affect everyone, but the poorest people and communities of color are most vulnerable.
Climate Change Impacts on Forests
The trees in forests absorb carbon dioxide, a key greenhouse gas, from the air. As temperatures increase, trees can become less healthy and die. This can lead to forest extinction, which is devastating for the species and communities that depend on them.
Loss of Rainfall and Desertification
Some regions are experiencing droughts, which can cause flooding, mudslides and other severe weather events. This can damage infrastructure and crops. It can also harm livestock and wildlife.