Increasing heavy downpours, fueled by climate change, cause billions of gallons of sewage overflows nationwide. Read the Climate Central report. Heavy rain in Louisiana deluge was 40 percent more likely and 10 percent heavier as a result of climate change.
Learn more on WWA. Across most of the country, the heaviest downpours are happening more frequently, delivering a deluge in place of what would have been routine heavy rain. Read full report. Interested in receiving weekly, location-specific updates on climate trends and topics? Click here. Use WeatherPower to bring wind and solar electricity generation into your forecasts, based on your local installed renewables capacity.
Localized data, analyses and multimedia — all grounded in science — to help you understand and share the story of our changing climate. Learn more Climate change made it even wetter than that. At NCAR, Pendergrass is working with global climate models to pin down what this might mean for extreme events in the future — and especially, where they might occur.
She analyses how climate change is altering how heat and energy flow in the atmosphere, which changes how precipitation is spread around the globe. Last year, she and her colleagues reported on three computer simulations showing that precipitation is likely to become more variable across almost all land areas if temperatures rise through the rest of the century 4.
In other words, weather will get crazier: wet periods will give way to dry periods more erratically, and vice versa, across nearly all the continents. Now, she has drilled down to study the unevenness of precipitation — that is, the difference between a light drizzle and a torrential downpour. Looking ahead with a climate model, the researchers found that this kind of unevenness will increase.
If greenhouse-gas emissions continue to climb quickly in the future, half of the extra rainfall will happen during the wettest six days of the year. Pendergrass has been talking with water managers in Denver, Colorado, who want to know how much flooding they need to prepare their dams to handle in the future.
She says other areas should prepare, too. Source: E. Knutti Nature Clim. Change 5 , — Another set of simulations underscores how society needs to prepare for these swings between wet and dry. This work, led by atmospheric scientist Zachary Zobel while he was at the University of Illinois in Urbana—Champaign, took a global climate model that usually calculates conditions every kilometres and forced it to a much higher resolution, of just 12 kilometres.
At a resolution of 12 kilometres, the model can reveal small-scale phenomena in the atmosphere that are important for simulating storms. Even using a supercomputer, it took the better part of a year for the model to crunch through its calculations 6.
But in the end, the researchers got a detailed look at how different parts of the country would be affected, in both temperature and precipitation extremes, if greenhouse-gas emissions continue to remain high out until The scientists found that extreme precipitation events would increase over most of the country.
They also spotted some larger changes in future patterns, such as in the position of the west-to-east jet stream that controls weather over much of the middle part of the United States.
That change arises because the Arctic is currently warming faster than are the mid-latitudes, so there is less of a temperature difference between the two regions. In response, the jet stream shifts northward in the simulations, bringing warm moist air from the Gulf of Mexico behind it.
Meanwhile, dry spells will grow longer, the model suggests. For Andreas Prein, the future hit home in , when heavy summer rains drenched central Europe. Today, Prein is an atmospheric scientist at NCAR and a leader in a new type of high-resolution climate modelling. Its computations narrow down to scales of four kilometres or less — which is so computationally expensive that it can be done only for relatively small regions. The field is known as convection-permitting climate modelling, and it allows researchers to simulate storms much more realistically.
The calculations are similar to what weather forecasters do to predict how storms will develop over the next day or two. In ongoing work, UK-based researchers have been running European-wide climate simulations at 2. In the simulations of a warmer world, summer downpours get heavier, and extreme events occur later in the year. That suggests officials might need to do more to prepare for flooding from winter storms.
This set-up effectively pointed an atmospheric fire hose at southern California. Taking a look at where things stand as of January 16, the recent rains have brought the water year closer to normal. However, if we look back at past history, most years this dry by this point have ended their water year with below-average precipitation in San Francisco, San Diego and Los Angeles, with more of a mixed bag in Sacramento. This was not overwhelming odds, but more likely than any other option.
Imagine if by divine wish, you were granted a hat that when worn while playing blackjack increases the number of aces you receive. Over the course of the night, I bet that hat leads to you winning more money than you would have otherwise. However, if I showed up to see one or two single hands of blackjack, I very well could have seen you bust.
These periods followed a similar pattern as those in January. A few more or a few less atmospheric river events could mean the difference between a well above-average year and a dry one. For more nerdy info, check out this article by Dettinger et al. Your name. About text formats. Very wet water year ends in California. How Permanent is Permafrost? Sea Surface Temperature Anomaly—December And the data also show more of those events per year.
Najjar said the extreme rain events cause more erosion and runoff, which ends up in rivers and oceans. As temperatures rise, so might evapotranspiration — the evaporation of river water into the atmosphere. Collier also cited the likelihood of more intense droughts as well as more intense floods and storms.
That means rivers may not always run high and fast. In Pa. UN: Greenhouse gas emissions hit a new record in
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