Jet Contrails Worse for Climate Change Than Aircraft Carbon Emissions

By John Timmer, Ars Technica

Air travel has come under fire for its potential contributions to climate change. Most people probably assume that its impact comes through carbon emissions, given that aircraft burn significant amounts of fossil fuel to stay aloft. But the carbon released by air travel remains a relatively minor part of the…

Sourced through Scoop.it from: www.wired.com

>” […]Others include the emissions of particulates high in the atmosphere, the production of nitrogen oxides and the direct production of clouds through contrail water vapor.

Over time, these thin lines of water evolve into “contrail cirrus” clouds that lose their linear features and become indistinguishable from the real thing.

Although low-altitude clouds tend to cool the planet by reflecting sunlight, high-altitude clouds like cirrus have an insulating effect and actually enhance warming.

To figure out the impact of these cirrus clouds, the authors created a module for an existing climate model (theECHAM4) that simulated the evolution of aircraft-induced cirrus clouds (they could validate some of the model’s output against satellite images of contrails).

They found hot spots of these clouds over the United States and Europe, as well as the North Atlantic travel corridor.

Smaller affects were seen in East Asia and over the northern Pacific. Over central Europe, values peaked at about 10 percent, in part because the output of the North Atlantic corridor drifted in that direction.

On their own, aircraft-generated cirrus produces a global climate forcing of about 40 milliwatts per square meter. (In contrast, the solar cycle results in changes of about a full watt/M2.)

But these clouds suppressed the formation of natural cirrus clouds, which partially offset the impact of the aircraft-generated ones, reducing the figure to about 30 mW/M2. That still leaves it among the most significant contribution to the climate produced by aircraft.

Some reports have suggested we might focus on makingengines that emit less water vapor, but the water is a necessary byproduct of burning hydrocarbon.

We’ll almost certainly be accomplishing that as a result of rising fuel prices, and will limit carbon emissions at the same time.

The nice thing is that, in contrast to the long atmospheric lifespan of CO2, if we can cause any changes in cloud formation, they’ll have an impact within a matter of days. […]”<

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It’s Time Our Policies Reflect The Fact That Energy And Water Are Fundamentally Intertwined

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For a long time, we’ve overlooked the inextricable relationship between water and energy use.  Coal, nuclear and natural gas plants use enormous amounts of steam to create electricity.  Producing all of that steam requires 190,000 million gallons of water per day, or 39% of all freshwater withdrawals in the nation.

Duane Tilden‘s insight:

>The longstanding division between energy and water considerations is particularly evident in the case of energy and water management.  These resources are fundamentally intertwined: Energy is used to secure, deliver, treat and distribute water, while water is used (and often degraded) to develop, process and deliver energy.

Despite the inherent connection between the two sectors, energy and water planners routinely make decisions that impact one another without adequately understanding the scientific or policy complexities of the other sector.  This miscommunication often hides joint opportunities for conservation to the detriment of budgets, efficiency, the environment and public health, and inhibits both sectors from fully accounting for the financial, environmental or social effects they have on each other.

This lack of collaboration between energy and water planners is especially dire considering Texas is in midst of an energy shortage that is exacerbated by the multi-year drought.  Without adequate planning, we could someday have to choose between keeping our lights on and turning on the faucet.<

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Heat Wave May Threaten World’s Hottest Temp. Record | Climate Central

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By the end of an upcoming heat wave, we may see a new record for the hottest temperature ever recorded on Earth.

Duane Tilden‘s insight:

>All-time records are likely to be threatened in normally hot places — including Death Valley, Calif., which holds the record for the highest reliably recorded air temperature on Earth at 134°F. That mark was set on July 10, 1913, and with forecast highs between 125°F to 130°F this weekend, that record could be threatened. The last time Death Valley recorded a temperature at or above 130°F was in 1913.

Las Vegas and Phoenix, two cities well-known for their hot and dry summers, are also predicted to approach all-time record territory. Last Vegas’ all-time high temperature record is 117°F and Phoenix’s high is 122°F. Excessive heat warnings are in effect in both cities from Friday through Monday.

Las Vegas could come close to tying its record for the longest stretch of days at or above 110°F, which is 10 straight, set in 1961. Phoenix may approach its record for the number of consecutive days at or above 116°F, which is four, set in 1990. Reliable weather records began there in 1896. Forecast highs in Phoenix range between 115°F to 120°F for Friday through Sunday.<

See on www.climatecentral.org