The National Climate Assessment, a stunning report published in November by 13 federal agencies and the White House, showed that climate change has already had devastating consequences for our health and the economy and that spending can reach hundreds of billions of dollars. the end of the century.
The report outlines what we can expect if we now aggressively reduce greenhouse gas emissions and what happens if we do nothing. As part of our Weather 2050 project, we used the latest scenario to look at what could happen with temperatures and rainfalls in American cities by the middle of the century.
We have found that by 2050 many American cities today may resemble hotter and more southern parts of the country. Here we've mapped some of the most impressive transitions:
As you can see in this map, climate change means that cities can move further south in terms of temperature and rainfall patterns. In some cases, the closest match can be hundreds of miles. If you want to get an idea of what climate change can mean for your city, you may need to make a trip.
By 2050 in Cleveland, Ohio, the average summer will warm up by 5.4 ° F. The average low of the winter will rise by 5.3 ° F. This means that Cleveland will have a suburban St. Louis climate on more than 500 miles.
Let us increase the way the climate in the various regions can shift. Check out this animation of changes in the Northeast US:
You can see that Scranton, Pennsylvania, will have a climate that resembles that of Round Hill, Virginia, today. This is about 220 miles in a straight line, but this means that Scranton will encounter average summer peaks that are 4.8 ° F higher and winter lows that are 5.5 ° F higher.
We can also see this in the South East of the United States:
The cities in the south are moving further south. By 2050, the annual temperature and precipitation patterns in Atlanta, Georgia, will look like Selmont, Alabama, today. This is a move of more than 200 miles, with the average summer high jump from 4.1 ° F to 92.6 ° F.
Other parts of the country may see smaller shifts by 2050, as you can see in this map of Southwest:
Apache Junction, Arizona, is likely to experience a year-round climate, more like Peoria, Arizona, a city just 50 miles west. But it still means that the average summer high today, 103.5 ° F, will rise by 4.9 ° F by 2050.
As you can imagine, the changes will be even bigger by 2080. And in February (two months after this story was first published), two scientists discovered in Nature Communications a new climate mapping project for the US that shows that by 2080 "the climate of most urban areas will shrink considerably and become closer to the modern climate of hundreds of kilometers and mostly to the south or there will be modern equivalent ". Play with their fascinating interactive here.
What does climate change mean for the US?
For each individual city, several degrees of heat and a few extra or less inches of rain in a season may not look much. But it may be the difference between enough rain for healthy crops and drought that kills them. This is the difference between wet winter and white winter.
Not every part of the country changes with the same speed. In general, the more northern parts of the US are warming faster than the southern ones, so climate change is greater. Cities in the eastern US and upper Midwest will likely see bigger changes than those in the West.
It is clear, however, that hundreds of cities will have to adapt to changes that could be quite profound for people's lifestyles. More homes will need air conditioners as summer is filled with deadly heat waves. More vegetation will dry out, creating more fuel for fires. This in turn can affect the local economy as climate-dependent industries such as agriculture or a drop in outdoor tourism.
It is important to note that the average values we quote do not tell the whole story. Some of the more moderate parts of the United States, such as the California coast, will see sharper fluctuations in their time. Instead of spreading rainfall throughout the year, California is expected to see periods of intense rainfall followed by extreme dryness, which the phenomenon describes as a phenomenon.
The planet as a whole has already warmed 1 ° C from the industrial revolution zone and we are currently about to see 2 ° C warm up by 2040. But we still have the opportunity to prevent the worst case. script. And we already know what to focus on. They are here 10 ways to accelerate progress on climate change and a simple guide to current climate policies.
How did we make these cards?
We generated our city pairs by comparing our future annual weather and rain forecasts with all-weather climate models today, looking for current and future cities that are most closely connected.
In order to build our comparisons, we have averaged daily minimum and maximum temperatures and rainfall patterns for each month for 30 years (from 1986 to 2015) to create a baseline climate for cities. We then looked at how these cities will warm up by 2050, again on average over 30 years (2036 to 2065).
These predictions are based on a set of climate models summarized in the localized constructed analogue data set developed by the Scrip Institute of Oceanography at the University of California San Diego.
The scenario here is built on a standard set of assumptions in climate models known as RCP 8.5. This is generally regarded as a high estimate of warming, as it implies that the world will continue in the same way with carbon dioxide emissions with limited improvements in technology or efficiency.
However, she closely follows where we are now and serves as a useful upper limit to what we can expect. RCP 8.5 also does not lead to a huge difference in climate change assessments compared to other scenarios when viewed mid-century. The largest variations in RCP 8.5 occur around 2100.
There are several important warnings for our analysis. Part of the reason why we do not see such big geographic changes in similar cities in the south is that we do not have enough cities farther south to compare. Our dataset includes only the continental part of the United States, but the city of Texas may see its climate as a city in Mexico, and one city in Florida may resemble an island in the Caribbean. So there were many southern cities for which we have no matches at all. We chose the best available matches with the data we have.
We also compare cities only on the basis of temperature and precipitation by looking at which cities today are the most similar to predicted changes in a city by 2050. These are just two variables from dozens that determine the local climate. In addition, weather forecasts up to the middle of the century are more resilient than precipitation patterns, which are much more dependent on local variables and more uncertainty.
However, the greatest uncertainty here is the same as for all climate forecasts: How quickly will we act on climate change? Whether the world will move to cleaner energy, eat less meat, better manage the earth, extract the carbon dioxide from the air or stick to the business as usual, means a significant degree of future warming.
What we are doing here is really important for our native places, our country and future generations around the world.