What causes a tornado?
Tornadoes are formed by a combination of atmospheric instability and wind shear. Instability occurs when warm, moist air is wedged under drier, cooler air aloft. This warm air rises, causing the intense updrafts and downdrafts seen in strong thunderstorms — the incubators of tornadoes. Wind shear refers to changes in wind direction and speed at different elevations in the atmosphere. The combination of instability and wind shear forms the circular air flow that generates a tornado.
Why are there so many in the U.S. Midwest?
The Central United States has an abundance of the ingredients necessary for tornado formation. During the spring, warm tropical air masses from the Gulf of Mexico collide with colder, drier air at higher altitudes to spawn intense thunderstorms. Thunderstorms also form into the summer and fall, as the region’s vast plains heat up air near the surface, causing atmospheric instability. These intense thunderstorms act as incubators for tornadoes. Tornadoes occur around the world but are most common in “Tornado Alley” of the Central United States.
Is there a link between climate change and tornadoes?
It is important to keep in mind that climate change has an impact on all weather events. The effect of the carbon dioxide in our atmosphere cannot be switched off – it influences our seemingly benign “everyday” or “normal” weather as well as the extreme events.
A specific link between tornadoes and climate change, however, is unclear. It is difficult to identify and diagnose trends in long-term records of tornadoes, since the population in many areas affected by tornadoes has grown (e.g., tornadoes in the early part of the 20th century may have occurred without anyone seeing them) and the technology used to observe tornadoes has improved (e.g., radars help us “see” tornadoes in ways that were not possible many decades ago).
How could climate change affect the frequency or intensity of tornadoes?
Researchers are working to better understand how the building blocks for tornadoes -- atmospheric instability and wind shear -- will respond to global warming. It is likely that a warmer, moister world would allow for more frequent instability. However, it is also likely that a warmer world would lessen chances for wind shear. Recent trends for these quantities in the Midwest during the spring are inconclusive. It is also possible that these changes could shift the timing of tornadoes or regions that are most likely to be hit.
Adding to the difficulty, tornadoes are too geographically small to be well simulated by climate models. Models can simulate some of the conditions that contribute to forming severe thunderstorms that often spawn tornadoes. Multiple studies (e.g., here and here) find the conditions that produce the most severe thunderstorms are likely to occur more often in the in a warmer world, even if the total number of thunderstorms decreases (because of fewer weak storms). However, this work does not conclusively tell us whether tornadoes should follow the same trend as their parent thunderstorms.
On May 16, 2013, Governor Chris Christie of New Jersey revealed a plan to spend $300 million of Federal Emergency Management Agency (FEMA) funds to buy out homes in flood-prone areas affected by Hurricane Sandy in October 2012. This program will give homeowners in Central New Jersey the opportunity to move instead of rebuilding in an area that is at high risk to flood again. The plan is based on the idea that the costs of relocating homes away from flood-prone areas will be lower than the cost of continuously rebuild flood- or storm-damaged homes
Called the “Willing Seller” Plan, this program is completely voluntary. In addition, it will target neighborhoods rather than individual homes, so that the bought out land can be razed and become open space. The program is targeting nearly 1000 homes in the central coast area of Jersey and will start with around 350 homes in Sayreville, which is located in the floodplains of the Raritan River.
The timeline for this program is short. Property appraisals will begin in June, and the first round of buyouts are expected to be completed by Labor Day. The entire program is scheduled to take just one year. The New Jersey Department of Environmental Protection (DEP) will handle the purchasing and the State Office of Emergency Management (OEM) will procure funds through FEMA.
This plan is an extension of the state’s Blue Acres Floodplain Acquisitions program, a voluntary buyout program for flood-prone homes that began in 1995, but has been low on funds since 1998 because of a high demand for buyouts. In contrast, demand for New York’s post-Sandy buyout program has been lackluster as most homeowners are choosing to stay and rebuild.
For more information:
State of New Jersey: Press Release
C2ES: Extreme Weather Map
On May 15, 2013, two new pieces of legislation to lower financial barriers to using plug-in electric vehicles (PEVs) were passed into law in Colorado by Governor John Hickenlooper. Financial incentives play an important role in keeping PEVs competitive in the automobile market.
House Bill 1247, called the Innovative Motor Vehicle Income Tax Credit, secures state tax credits up to $6000 for electric vehicle purchasers or lessees until 2021, which would have otherwise expired in 2015. The bill specifically covers any EV that can be recharged from external sources, including plug-in hybrids. The bill also covers vehicles that are converted into PEVs, which are eligible for a tax incentive of $7500. This law will take effect in January 2014.
House Bill 1110, called the Special Fuel Tax & Electric Vehicle Fee, establishes a flat, annual fee of $50 for the registration of each plug-in electric vehicle. Sixty percent of the fee replaces the revenue not collected from gasoline taxes and goes toward road and highway maintenance, while the other forty percent funds electric vehicle infrastructure such as charging stations. Colorado’s PEV fee as established by HB 1100 is low compared to those considered by other states, which are around $100 or calculated based on mileage and do not fund PEV infrastructure. This law will take effect in January 2014.
According to Denver Clean Cities, as of July 2012, there were almost 1,300 registered PEVs and around 70 charging public charging stations in the state. However, this number is likely to grow because Colorado is relatively generous with policies supporting electric vehicles.
According to one source, Colorado is the leading state in the region when it comes to PEV policy. A state government report card from Southwest Energy Efficiency Project (SWEEP) awarded Colorado with a grade of “A-” for its twelve policies that support electric vehicle adoption, including the two laws mentioned above. Colorado does not fare quite as well as California, however, which would earn an “A+” under SWEEP’s methodology because of its major commitment to install fast-charging stations along highway corridors and for 15% of cars sold in the state by 2025 to be plug-in electric vehicles.
For more information:
C2ES: Common Concerns about EV Policy
C2ES: PEV State of Play and PEV Literature Review
C2ES: Powering More Travel with Electricity Map
C2ES: PEV Dialogue
plugincars: Colorado Extends $6,000 Plug-in Vehicle Credit Through 2021
I recently replied to a question on the National Journal blog on whether small legislative measures will be effective in fighting climate change.
You can read responses at the National Journal.
Here is my response:
The Center for Climate and Energy Solutions (C2ES) and the University of Texas launch their new report, "Leveraging Natural Gas to Reduce Greenhouse Gas Emissions," outlining the climate implications of expanded natural gas use and potential uses and benefits in key sectors. C2ES President Eileen Claussen will lead a CEO-level conversation and Michael Webber, deputy director of UT’s Energy Institute, will lead a discussion of sector-specific recommendations for capitalizing on natural gas in power generation, buildings, manufacturing and transportation.Tue, 06/04/2013 - 09:00 - 11:30
President, Center for Climate and Energy Solutions
Vice President, Energy Policy, Center for American Progress
CEO, Dominion Resources
President, American Gas Association
Deputy Director, Energy Institute, The University of Texas at Austin, Moderator
Technical Director, Institute for Industrial Productivity
Vice President - Marketing and Business Intelligence, New Jersey Natural Gas
Federal Public Affairs Director, Waste Management
Executive Director, Deloitte Center for Energy Solutions