The last time levels were that high was about three to five million years ago, during the Pliocene Epoch.īecause we are already committed to some level of climate change, responding to climate change involves a two-pronged approach: In 2013, the daily level of carbon dioxide in the atmosphere surpassed 400 parts per million for the first time in human history. Despite increasing awareness of climate change, our emissions of greenhouse gases continue on a relentless rise. How much climate change? That will be determined by how our emissions continue and exactly how our climate responds to those emissions.
In this way, humanity is “committed” to some level of climate change. So even if we stopped emitting all greenhouse gases today, global warming and climate change will continue to affect future generations.
Carbon dioxide, the heat-trapping greenhouse gas that is the primary driver of recent global warming, lingers in the atmosphere for many thousands of years, and the planet (especially the ocean) takes a while to respond to warming. It involves many dimensions – science, economics, society, politics, and moral and ethical questions – and is a global problem, felt on local scales, that will be around for thousands of years. Climate change is one of the most complex issues facing us today.
