Even though it’s only the 9th of July, nearly 3,400 maximum and minimum temperature records have been tied or broken so far this month. Dozens of people have died and the lack of rainfall combined with the extreme heat is threatening the Midwest’s corn crop. In the Rocky Mountain region, wildfires have swept across the area, fueled by dry conditions and high temperatures. The fires have already burned through hundreds of thousands of acres and destroyed hundreds of homes.
So, can we link these extreme weather patterns, and the damage they cause, to climate change? Climate deniers would argue that there is no extreme weather pattern and, in fact, we are in a period of global cooling. And, too often, the debate around climate change focuses on whether there is a direct, immediate causal link between increased temperatures and carbon dioxide emissions. Meaning, people look for a relationship as simple as increased carbon dioxide equals immediate extreme weather.
In reality, the science is far more complicated and more important than an immediate 1:1 causal link is the very clear trend towards sustained increased warming. While more than 60,000 hot temperature records have been set since January 1st in the United States, less than 6,000 cold temperature records have been set. In most of the last century, the hot to cold record setting ratio was close to one to one. In the past decade, there has been more than double the number of hot records, and this year, the ratio is 7:1. This ratio could be as high as 20:1 by midcentury.
Moreover, the link between carbon dioxide levels and warming was seen in a much earlier time period when a release of greenhouse gases caused global temperatures to increase. While climate deniers will use this evidence to again point to global warming as a natural phenomenon, in fact it shows that greenhouse gases do cause warming and the levels of gases correspond to the level of warming. The levels of greenhouse gases that are being emitted now are far greater than what naturally occurred during the previous warming period.
During the previous warming period, scientists estimate that between 300 million and 1,700 million metric tons of carbon dioxide was emitted into the atmosphere per year. In 2011, 31.6 Gigatons of carbon dioxide was emitted, a substantial increase that can be directly attributed to the increase of carbon dioxide from man made activities. This means that whatever impacts from warming occurred naturally will be magnified due to the increased intensity of higher carbon dioxide levels.
Without a substantial decrease in carbon dioxide emissions, we can expect more extreme weather patterns, and as our climate change reports show, the economic impact of warming will push states and populations further into economic insecurity. We need to pivot to a clean, low-carbon economy and we need to do it now. The longer we wait, the harder it will be to avoid the more severe impacts and the higher the costs-- for the environment and our economy-- will be.