Cars News and Reviews Energy Transition: Moving Into a Better Future- CARS NEWS AND REVIEWS

Posted by Carmella Ross on Monday

On 20 October, 2013 my brother, one of the most important men in my life, was married in a beautiful outdoor ceremony, surrounded by the love of family and friends and by the peace of nature, the whole suffused in brilliant sunshine. His bride, my new sister, was even more radiant than she usually is.



Photo Jason Hutchens

Neither of them are extremely young. They have each seen quite a bit of the world, sometimes on their own, sometimes in a relationship, so far transitory. They have known the advantages to being unattached. There is a certain kind of freedom that you enjoy if you only have to take care of yourself and no-one else.

Like many of us, these two people have decided to give up that freedom, in exchange for a formal and lasting connection, made of their own free will, in a leap of faith that their life together will be better than the separate lives they are leaving behind. The bride's best friend, her honorary brother, read this poem at the ceremony:

 

Standing on the edge of my open heart

     I leap into the air

     sweet, breathable, yet unknown,

What awaits me I do not pretend to undertand;

     I will open my arms of my days

     and fly into this horizon

                                     Janet Childs

 

This kind of thing takes courage. A marriage is a celebration, not only of the couple's future life, but also of their courage in having overcome the fear of the unknown: the possibility of having to deal with their partner's ditry socks strewn all over the floor, and other annoying habits as yet undiscovered, other vagaries of a life together.

In this we are like the explorers of old, back when the Earth still had large pieces of Terra Incognita, and when people still warned you of falling off the edge if you went too far, or of monsters that awaited you in unknown seas.

Those warnings didn't deter the Vikings, and later the Spanish and Portuguese explorers: they went ahead anyway, and loaded their too-small ships with men, supplies, and whatever navigation technology they had at their disposal, and set sail.

And found no large sea monsters. But a large new continent, filled with possibility. And beyond that, even more stunning, a vast new ocean, and eventually, the final proof that the earth is not flat but round, and can be circumnavigated. Probably the sestet of Keat's sonnet are still the best words to describe the wonder of discovery:

 

On First Looking into Chapman's Homer

Much have I traveled in the realms of gold

     And many goodly states and kingdoms seen;

     Round many western islands have I been

Which bards in fealty to Apollo hold.

Oft of one wide expanse had I been told

     That deep-browed Homer ruled as his demesne;

     Yet never did I breathe its pure serene

Till I heard Chapman speak out loud and bold:

Then felt I like some watcher of the skies

     When a new planet swims into his ken;

Or like stout Cortez when with eagle eyes

     He stared at the Pacific—and all his men

Looked at each other with a wild surmise—

     Silent, upon a peak in Darien.

                                     John Keats

 

There is the excitement of the "wild surmise". There is a stunning into silence in the solemn acknowledgement of the opening of a whole new era, and a closing of the old. (Darien is what is now Panama).

The "watcher of the skies" is William Herschel, who built telescopes and peered through them at night, after his day jobs as the organist at the Octagon Chapel, as the Director of Public Concerts in Bath and as a music teacher at his home. His observations led to a whole new way of thinking about the birth of solar systems and indeed entire galaxies, and definitively displaced mankind from the center of the universe.

No two ways about it: these transitions and discoveries are scary.

But marriage lends to life a richness that, while not impossible, is very, very difficult to find on your own. The discoverers of the New World brought back with them the potato, tomato and corn, and (my favourite) the coffee bean. They also brought back the tobacco leaf, but we're mostly over that menace now.

After the Age of Discovery, Herschel's astronomical discoveries blew life into a whole new field of cosmology. And the steam engine was invented and put to work, replacing the power of so many horses - and so many slaves.

The rise of abolition was a scary time for slave holders, who had built a very comfortable life for their large families on the power of human labour. Many people in government had ties to slavery (think of Jefferson). People wrung their hands that abolition of slavery would bring about unimaginable disaster and social displacement, that the economy would be ruined; that slavery was the "natural" world order; that abolition would lead to the ruin of the former slaves; that the freed slaves might exact bloody revenge on their former masters.

In other words, that one cannot possibly transition from the energy of slaves to the new energy of coal and oil.

But the world did make that transition.

And now it is time to make the new transition. And it's scary for those of us who have built very comfortable lives on the power of fossil fuels. Many people in government have ties to the fossil fuel industry. People wring their hands that stopping the use of fossil fuels will bring unimaginable disaster and social displacement, that the economy will be ruined, that the development of natural resources is the natural world order, that the transition might give rise to hunger, rioting and bloody uprisings.

Guess what: we now look back and say, Yes, abolition was the obvious, the morally just thing to do. Fossil fuels helped better the lot of countless people, contributed to feeding millions, raised living standards. We're better off than before abolition. Besides, no number of slaves could propel you at 65 mph for hours at a stretch. Or get you and your luggage off the ground and wisk you off toward your vacation destination. Fossil fuels enabled us to do things that anti-abolitionists couldn't have dreamt of.

But for all the good things that the energy from fossil fuels has brought us, we are finding that it has its dark side, in the form of pollution, the encouragement of waste, and now climate change. Sometimes you find out that a relationship has become unhealthy. Then it's time to sue for divorce.

I'm not saying divorce is easy: in many ways it is just as scary as marriage. It's an upheaval. Like in the case of those major discoveries, it's easy to cling to the status quo that is unhealthy but familiar. But it's really time to break away: We all need to be like those explorers. We need to gather our courage, and trust that the new energy will not only get us away from the bad side effects of fossil fuel energy, but will bring us new possibilities that we cannot right now conceive.

Take heart: we can do this energy transition. After all, we've done it before, in getting away from the energy of slaves.

 

 

Shared at Simply Natural Saturdays

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Cars News and Reviews Review: Hyundai Elantra / Avante- CARS NEWS AND REVIEWS

Posted by Carmella Ross on Friday

For the occasion of my brother's wedding, my family completely ruined our carbon footprint for this year. Because this is the middle of the school year, we flew over for just a few days, and we rented a car so that my dad could come with us everywhere.

The rental car was a Hyundai Elantra, a four-door sedan. I was offered an upgrade at pickup time, but declined, figuring you shouldn't drive a rental car that's too much larger than the one you drive daily. I hear this car is popular with rental car agencies because of its good maintenance record.



The Elantra falls in the "Economy" rental bracket, which means it carried five of us comfortably. Our luggage rattled around in the large trunk, which could easily accomodate both our cellos. There were a few blind spots that were larger than I would like, particularly the bar between the front windshield and the side windows.

The Elantra had a slight drive-by-wire feel to the handling, but it wasn't overwhelming. Its 1.8L, 148HP engine was completely up to the job of moving the car even when fully loaded (five people plus luggage), even for quick insertions in rush-hour traffic.

Here is one of those few cars that is sold in the US with an engine comparable to that offered elsewhere (instead of significantly larger). The 1.8L engine is the only one available in the US (and in New Zealand also), but that is down from the former offering of a 2.0L gasoline engine. In Korea (where this car is named the Avante) there is choice of three drivetrains, all with a 1.6L volume.

The Korean Avante GDi runs on unleaded gasoline (33mpg), while the VGT runs on low-sulphur diesel, has a slightly lower power (128HP) but packs 50% more torque than the American 1.8L, at higher fuel efficiency (48mpg). [I take it that the Korean test cycle is now reasonably accurate, since they quote the Toyota Prius at 50mpg].

There is also an Avante Hybrid, which is unusual in that it is an LPG hybrid running on liquid petroleum gas (a mixture of propane and butane which tends to burn much cleaner, especially for particulates, than gasoline containing longer hydrocarbon chains). It is quoted at 33 mpg but puts out only 92 g CO2 / km. [For comparison, a gasoline engine doing 59mpg would exhaust 92 g CO2/km].

Also becoming more rare now is the 10-year, 100,000 mile limited warranty on the powertrain, which backs up the Elantra's reputation for reliability. Its fuel efficiency of 37 mpg as reported by real drivers is really very good, and you can't complain about the price tag.

Compared to the 1.8L gasoline available in the US now, I would expect the diesel version with the smaller 1.6 engine volume to have a similar price point. But it delivers 43 mpg, making it very attractive for the long run as well. I hope it will come to the US soon.

 

Hyundai Elantra / Avante






























Elantra (US) Avante (KR) Avante (KR)
Type GLS 1.6 GDi Style U2 1.6 VGT
Year 2013 2013 2013
Emissions rating ULEV    
MSRP $ 16,965 ₩ 13,950,000

(US $ 13,190)
₩ 15,950,000

(US $ 15,100)
CelloMom Rating
Fuel Economy:
City/Hwy quoted 28 / 38 mpg 12.5 / 16.7 km/L 16.9 / 20.8 km/L
Avg. quoted 32 mpg 14.1 km/L

(33mpg)
18.5 km/L

(43mpg)
Avg. actual 37 mpg    
Carbon emissions, quoted   122 g CO2 /km 103 g/km
Engine 1.8L, 16 vlv 1.6L 1.6L
Power 148HP @ 6500rpm 140 HP @ 6300rpm 128 HP @ 4000rpm
Torque 131 lb-ft @ 4700rpm 170 Nm

(125 lb-ft)

@ 4850rpm
265 Nm

(195 lb-ft) @

1900-2750rpm
Transmission 6-spd man 6-spd man 6-spd man
Fuel Reg. unleaded Unleaded Diesel
Length, mm(in) 178.3 in 4550 mm  
Width, mm(in) 69.9 in 1775 mm  
Height, mm(in) 56.5 in 1435 mm  
Weight, kg(lbs) 2661 lbs 1210 kg 1305 kg
Trunk volume, liters(cuft) 14.8 cuft    
Turning radius, m(ft) 34.8 c-c    
Top speed, kph(mph)      

 

 

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Cars News and Reviews The Warmest Day of Your Life - So Far- CARS NEWS AND REVIEWS

Posted by Carmella Ross

Okay, try this with me: Bring up the memory of the hottest day in your life. Picture it: Where were you that day? What were you doing? Who was with you? How did you cope with the heat?

I'll start.

The time was August 1988, a few weeks before the start of the academic year. The Northeast was gripped by a ten-day heat wave. I went to Boston's Logan Airport, to meet my then-boyfriend, who had decided to come to the US to go back to school.

He emerged from immigration and customs wearing a thin layer of perspiration. I could tell it wasn't my lovely presence that caused him to pant slightly.

"It's so hot!" was almost the first thing he said.

"Hot?" I said, "It's cool in here; this terminal has air-conditioning."

"This is air-conditioned?" he yelped. I could see a trace of panic come into his eyes. I suspect that at that moment he considered turning around and taking the next plane back to the pleasant Dutch climate. My poor boyfriend nearly passed out when we came outside into the heat and humidity. He spent the following days stretched out in front of a fan (I had no air conditioning then, either), while I fed him salads, iced lemonade, ice creams, everything cool.

Eventually, the heat wave passed. My boyfriend didn't turn back: he stayed, got his degree, and by and by became CelloDad. But it was a close call.

Now it's your turn.

Think back on that day, the hottest day in your life.



The fountains at the Philadephia Museum of Art, 1973

 

Now imagine that a time when such days happen a few times a year.

Then, a time when they happen pretty frequently.

I know, right? It makes you break out in a sweat just thinking about it. But it's coming unless we stop pumping carbon dioxide and other greenhouse gases into out planet's atmosphere, and it's coming sooner than we might think.

Climate change studies tend to depict scenarios around the year 2100: that's after my lifetime. I might not even see 2050. It's hard to wrap your head around dates that far into the future. But now a team led by Camilo Mora at the University of Hawaii at Manoa has put the data in a different light. It's eye-opening.

Climate Departure

Starting from the well-established climate data and models, Mora's team have computed the Year of Climate Departure for locations throughout the world. A place has reached climate departure when the average temperature of its coolest year from then on is expected to be higher than the average temperature of its hottest year between 1960 and 2005. It is the year in which that place has truly reached the "new normal" and its "old normal" is history.

Below is a world map with the year of climate departure indicated by colour, with a few cities highlighted. We've heard a lot about arctic sea ice melting, but this data shows that it is the tropical region which are first to reach climate departure, as early as 2020. This should worry us, because tropical species are much more vulnerable to changes in their environment than species in temperate zones. The group has posted an interactive map on which you can look up the Year of Climate Departure for your region.



When looking at data like this, we need to allow for the fact that climate scientists, like all scientists, are a careful bunch. They don't make statements that are not built on strong evidence. This is why their reports tend to understate the risks we face from climate change. They certainly don't include runaway warming scenarios. In fact, climate scientist Michael Mann has described this paper as "an overly rosy scenario". Well I'll be. Because if you look at the Climate Departure years for biodiversity, the picture is grim enough.

It's not just that we will sweat more: Our food chain might be in jeopardy within 25 years, or perhaps sooner. Before that food will merely get horrendously expensive. Species will migrate to milder climates. Well: it would be cool to have parrots and birds of paradise frequent our woods. But it won't work out that way: it's more likely that people in what are now temperate zones will be visited by scourges that are so far confined to tropical latitudes, like malaria, dengue fever, fast cockroaches and big spiders.

Canada's population is now concentrated near its boundary with the US because its northern reaches are too cold. But soon the US population might collect on the Canadian border trying to get away from the heat. Heck, at some point Canada might build a wall on its border to keep Americans out.

Is it hopeless? --No.

The map above is the "business as usual" scenario, where we keep burning fossil fuels and the CO2 content in the atmosphere has more than doubled to 936ppm by 2100. if we work very hard at limiting CO2 emissions, the outlook, though still serious, is not nearly as dire.

Here are a handful of reasons for hope:

From an article on TheStreet.com:

"33 leading U.S. businesses -- including eBay, Nike and General Motors -- released a statement ... supporting strong U.S. climate policies. And nearly 700 more companies have signed on to the "Climate Declaration" in the past month, most notably Microsoft. "

The cost of solar cells has dropped by 99% since 1977, which has caused a boom in the PV industry (see chart below). You know it's gone mainstream when IKEA starts selling solar panels. This must be the only place in the economy where I can be glad to see robust growth.

It took all of us to get us to this point. It will take all of us to get us back to relative safety. Make no mistake about it: we will all have to give up something. But we can't just sit back and wait for it to resolve itself. It really is up to us.

Join Citizens' Climate Lobby and pressure your elected representative to do the right thing. Doing the right thing is hard, and will not be popular: An article on The Hill's Energy & Environment blog says, "Imposing an explicit cost on carbon pollution is the best way to put countries on a path toward steep emissions cuts, according to new research by the OECD."

Don't wait for our elected "leaders" to lead: find ways to slash your own carbon footprint. Drive less, bike and walk more. Get informed, but choose your sources of information carefully: many are willfully misleading.

Hilal Elver in a piece at Al Jazeera:

"There is a great civilisation drama unfolding that pits the force and power of science and reason against the arrayed influence and power of money and vested interests in sustaining a petroleum-based economy long beyond its useful life expectancy. We, the public, have a great stake in the outcome of this struggle, and must not be content to stand meekly on the sidelines while the gladiators do battle."

 

Cross-posted at BlogHer; Shared at Small Footprint Friday

 

 

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Cars News and Reviews Radiative Forcing and Global Warming Potential- CARS NEWS AND REVIEWS

Posted by Carmella Ross on Tuesday

Sometimes science seems to use English words, but on closer inspection you find that the meaning of those words are not what you're used to.

"Positive Feedback" is a good example. At school, or at work, positive feedback is when you're complimented for a job done well. In the context of climate science, positive feedback often denotes a vicious cycle or self-reinforcing global warming, as in when waming leads to melting of permafrost, which releases methane (a powerful greenhouse gas), which in turn leads to further warming.



"Stampede Loop" by John Trevithick, a great example of a positive feedback loop.

I could think of a bunch of racier examples, but this is a general-audience blog, so I will refrain. Suffice it to say that sometimes scientists, with a straight face, will bandy about terms that in an ordinary non-scientific conversation would make you blush.

But back to global warming. The following are notes on my reading up about several terms that have been used a lot - but I realised I didn't quite understand. I learned that the fearfully named "radiative forcing" is simply the imbalance on the planet's energy balance sheet. That the term "global warming potential" is fraught with details, caveats and snags that nobody ever talks about. And I found out the reason for why people talk of the temperature rise associated with a "doubling of the CO2 concentration", rather than an increase by some amount.

There's a bit of math. That's okay: an equation is worth a thousand words. And math was the gateway through which I found out that some of the words used in the climate change discussion don't mean quite what I thought they did. So here goes.

 

The term "Radiative Forcing" gets used a lot in discussions on climate change. At first hearing, it might sound like the light emanating from the sun is pushing the earth into a larger orbit. But it's nothing of the kind.

Radiative Forcing (RF) is the difference between the radiant energy (per unit area, per unit time) received by the earth - mostly from the sun - and the energy radiated by the earth, back into space. The units are Watts per square meter (Wm-2).

Before the Industrial Revolution, the total RF=0, that is, the outgoing radiation exactly balanced the incoming radiation, so the earth was not accumulating excess energy, and did not warm (at least over the holocene, the last 10,000 or so years).

In the context of climate change, we are interested in the imbalance: anthropogenic CO2 emissions have caused the atmosphere to be more retentive of heat, so the earth is radiating less energy than it receives: this accumulation of energy is what causes global warming.

 

For the global warming due to a particular component of our planet, such as albedo, land use or any greenhouse gases, the IPCC defines radiative forcing as follows (my italics):

"Radiative forcing is a measure of the influence a factor has in altering the balance of incoming and outgoing energy in the Earth-atmosphere system and is an index of the importance of the factor as a potential climate change mechanism. In this report radiative forcing values are for changes relative to preindustrial conditions defined at 1750 (AD) and are expressed in Watts per square meter (W/m2)."

Here is an example for carbon dioxide (CO2). The earth radiates energy because its surface is warm, and the radiation has a spectrum that follows roughly the black body radiation spectrum, but modified by the atmospheric absorption. The absorption shows up as dips in the spectrum. The entire spectrum is in the far infrared (visible light would be at 19,000 - 28,000 cm-1).

The green line in the graph is the earth's irradiance for CO2 levels of 300 ppm. Wavenumber is the inverse of wavelength, measured in cm-1. Irradiance (on the y-axis) is the radiative forcing found over an interval of the spectrum; when graphed as a function of wavenumber, its units are Wm-2cm. The big dip around 660 cm-1 is the absorption band of CO2.

The blue line, for 600 ppm CO2, shows a slightly deeper dip at 660 cm-1, that is, the earth radiates less heat at the higher CO2 concentration. The difference doesn't look like much (more on that below), but integrating over the spectrum gives a total change in outward irradiance of ΔF=3.39 W/m2. This is the radiative forcing due to the additional 300 ppm of CO2.

[Incidentally, the sun's radiation also has a black-body spectrum. But because the sun's surface is much hotter than the earth's, the peak of the solar irradiance occurs in the visible, around 21000 cm-1 (or if you prefer thinking about wavelengths, around λ=590nm: yellow). This why the sun's incoming radiation doesn't depend on the concentration of greenhouse gases]

Carbon dioxide happens to be rather a difficult case: doubling the CO2 concentration does not make the absorption band at 660 cm-1 twice as deep. This is because CO2 is such a strong absorber that even at 300ppm it's well into the saturation region. The saturation effects cause the radiative forcing to have a logarithmic, rather than a linear, dependence on the CO2 concentration:

ΔF = 5.4 × ln (C/C0)

Here C is the CO2 concentration in ppm, and C0 is the reference concentration in the year 1750. This is why there is so much talk about "climate sensitivity", which is the amount of global warming following a "doubling" of CO2 concentrations: because of the logarthmic dependence, a doubling of the concentration will give a certain amount of radiative forcing that is independent of the starting concentration.

The current CO2 concentration is 400ppm, only 120ppm above pre-industrial values, so right now ΔF=1.9 Wm-2. The total anthropogenic radiative forcing, 2.3 Wm-2, is only 1.5% of the total average solar flux (150Wm-2), yet is enough to cause the global warming that represents such a threat to our species. Maybe it's that the planet is large: another measure of global warming is that our planet is accumulating the equivalent of four Hiroshima bombs worth of energy every second.

NOTE: the logarithmic dependence holds only for CO2. In contrast, ΔF for methane and N2O have a square-root dependence on concentration, while ΔF of a number of CFC gases have a linear dependence: these are far from the saturation limit. These are listed, with the coefficients, in IPCC's AR3.

Nature is just marvellous in its complexity. But it's not easy to talk about it in the kind of soundbites that the media is used to feeding us.

 

In case RF wasn't complicated enough, now let's talk about Global Warming Potential (GWP).

Remember, radiative forcing is the rate at which heat is retained in the earth's atmosphere instead of being radiated out into space. That's why its units are W/m2. But it doesn't tell you about the total heat retained by the earth because of an emissions of some greenhouse gas.

[In everyday terms: your hair dryer might use 1500 W of power. But the energy consumed (and the amount of heat you release in your bathroom) depends on how long you have the hair dryer turned on. If you've used it for half an hour, that's 750Wh, or 0.75kWh. If your teenage daughter busies herself with it for a whole hour, she will contribute 1.5kWh to the household energy use stated on your electricity bill (and you may want to talk to her about the risk of hearing damage) ].

Energy is power multiplied by the time it is applied. SI units doesn't use kWh, but Joules: 1J=1Ws=1 Watt-second. Heat is one particular kind of energy, and is also measured in Joules.

I'm going on about this because knowing the radiative forcing due to some of greenhouse gas (GHG) is not enough to tell you how much total warming that gas will cause: for that you need to integrate the radiative forcing over the lifetime of the gas. Each gas has its own lifetime in the atmosphere, ranging from hundreds of years in the case of CO2, to a few weeks for tropospheric ozone. For methane it's about 12 years.

So while methane may be a much feistier greenhouse gas than carbon dioxide, it has much less time to wreak its havoc. The concept of global warming potential attempts to make a reasonable comparison between the long-term climate effects of these disparate greenhouse gases.

Let's look at IPCC's definition of global warming potential: "The GWP has been defined as the ratio of the time-integrated radiative forcing from the instantaneous release of 1 kg of a trace substance relative to that of 1 kg of a reference gas":

GWP \left(x\right) = \frac{\int_0^{TH} a_x \cdot \left[x(t)\right] dt} {\int_0^{TH} a_r \cdot \left[r(t)\right] dt}

where TH is the time horizon over which the calculation is considered; ax is the radiative efficiency (same, as far as I can tell, as radiative forcing) due to a unit increase in atmospheric abundance of the substance (so its units are Wm-2 kg-1) and [x(t)] is the time-dependent decay in abundance of the substance following an instantaneous release of it at time t=0. The denominator contains the corresponding quantities for the reference gas CO2.

If I read the description of GWP in AR3 correctly, this definition uses a perturbative approach: GWP is the global warming response to the emission of a small additional amount of greenhouse gas x , in the presence of the other greenhouse gases that are already around. It's analogous to the marginal cost in economics. It depends, among many other things, on the time scale over which you look (TH) and the concentration of all the greenhouse gases already present.

The reference gas, CO2, is an unfortunate choise, because it is such an unruly beast (non-linear density dependence, rather intractable lifetime). So GWP may not be the greatest choice of measures by which to compare the badassedness of a particular greenhouse gas.

But this is the measure we've got, and as long as you remember all the caveats, which none of the journalists ever mention, GWP does give you the relative impact of a small additional amount of a given greenhouse gas, at least as compared to the major bad actor, CO2.

A list of GWP for the most common greenhouse gases shows the values for TH=20 years and TH=100 years. Another caveat: water is too slick to handle because its GWP depends on a huge number of parameters, not the least fluctuating of which is the temperature. So that's left out of the discussion altogether, even though we know from daily experience that a cloudy sky or even high humidity makes for warmer nights than a clear one.

It was pointed out quite early on (and repeated in AR5) that there is no scientific case for choosing to report GWP at 100 years rather than over some other time horizon. The choice of time horizon is a "value judgement". Meaning, there is space here for manipulation and misinterpretation. Also, if we ever get in the situation of runaway global warming, the relevant time horizon becomes the lifetime of the main cause of the positive feedback, very probably methane.

 

If you are interested in the global warming caused by the emissions of a unit amount of gas, you don't normalise to CO2, you would simply retain the numerator of the equation defining GWP, and integrate out to infinite time, to get the absolute global warming potential, AGWP, which has units Jm-2kg-1.

AGWP = ∫0∞ ax·[x(t)] dt

If you want to know how much heat the earth retains as the result of greenhouse gas emission, the AGWP needs to be multiplied by the surface of the earth, and the total mass M of the emitted greenhouse gas:

ΔE = 4πR2 M ∫0∞ ax·[x(t)] dt

The units for ΔE is Joules. As an example, the oceans are where 93% of the planet excess heat is absorbed. The change in heat content of the oceans since we started burning fossil fuels is now close to 2x1023 Joules.

I repeat the caveat: The above formula only holds for incremental amounts of GHG emission (small M), for those GHGs which don't have a linear concentration dependence. See the discussion of nonlinearities under radiative forcing.

 

If you're interested in what kind of temperature rise a given amount of GHG emissions would cause, you need the Global Temperature change Potential, or GTP. Here, "temperature" refers to the global mean surface temperature, so GTP depends also on how the retained heat is distributed among the atmosphere, the land and the oceans. So its estimate encompasses the entire geological complexity that makes this planet such a wonderful place to live on.

It is a testament to climate scientists' prowess and tenacity that global warming predictions have been so accurate.

 

 

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Cars News and Reviews Cellomomcars.com Moved to cellomomcars.blogspot.com- CARS NEWS AND REVIEWS

Posted by Carmella Ross on Monday

CelloMom is having some domain name issues, but the blog is alive and well, and can be accessed at cellomomcars.blogspot.com. Some links may not be updated yet; if you come across any, I apologise. Just insert the extra "blogspot" in the URL.

If you subscribe to my RSS feed, you may have missed posts for the month of September. They are listed below if you want to catch up.

Seven Ways to Keep Your Teen from Texting While Driving

The Toyota Yaris is Not a "Teen" Car

Two Cellos in the House

Global Warming Denialism May Have Origin in the Victorian Frame of Mind

Let's Talk with Our Children about Global Warming, with Sense and Sensitivity

How My Children's School Greened Me

Teach Your Parents Well: Children's Views on Climate Change

Wake Up: Garbage Trucks Ready to Dump on Your Lawn

 

 

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Cars News and Reviews Of Electric Vehicles and the Intergluteal Cleft- CARS NEWS AND REVIEWS

Posted by Carmella Ross on Saturday

In case you were wondering, the intergluteal cleft is popularly known as the "butt crack": that which becomes visible when you wear low-hung jeans and do anything but stand up straight.

Such jeans are also known as "plumbers' pants" not because plumbers are excessively fond of them compared to those of other professions, but because when they work under your sink they display the defining property of these sagging pants.

 photo Butt_Crack.jpg

Urban legend has it that wearing sagging pants originated in the US prison system, and were popularised by hip-hop artists in the 1990s, who turned the sagging pants into a fashion must-have. At first, really not that many people wore their pants that way. But now sagging pants have spread into the mainstream to the point that jeans for women are "low-rise" by default and you have to work hard to find a pair of jeans that hug your hips instead of miraculously hanging off them, seemingly defying gravity.

So now you know. But not to worry, this is a serious post. Electric cars are not to be the butt of any jokes cracked by me.

Electric cars, in fact, are very serious business. Over the past few years their sales have soared, and the discussion has finally shifted from range anxiety to the installation of charging points in this and that city.

But so far, and despite some price cuts, EVs have remained expensive. So it's not surprising that it is particularly the well-to-do who tend to buy them. In a survey published by the Wall Street Journal it was found that the 1% were over-represented in EV purchases during 2012: Among buyers of Leafs and Volts, over 30% had annual household incomes over $200,000, and nearly 4 of 5 had household incomes over $100,000.

So EV ownership is confined to a tiny fraction of the general population, very similar to how sagging pants used to be confined to a tiny fraction of the population. Just how skewed this distribution is becomes apparent if you compare it to who buys cars in general. The answer: everybody. For the purchase of all cars, the distribution is quite flat:

But, as with the sagging pants, the skewed distribution for EV ownership can't last. It must dissolve into a much flatter distribution, and it will eventually look pretty flat also, as EVs continue to penetrate the market. The very fact that it is still generally perceived as a rich man's toy contributes to the appeal of electric cars. (The survey shows results only for Leafs and Volts. If Teslas had been included the distribution would have been even more skewed toward high-income households).

Practical appeal is added by financial incentives and such privileges as the use of HOV lanes and special parking spots with chargers. California has spearheaded the installation of such incentives, which is probably why two cities, San Francisco and Los Angeles, account for more than 35% of EVs covered in the survey. But as it usually goes with these things, soon the nation will follow where California leads the way.

And the price of EVs will come down further (especially if it's helped by a judiciously placed carbon tax, that is heavier for larger polluters). I remember when a floppy disk with a storage capacity of 128kilobytes (kilobytes!) cost around $100 and a personal computer was for the eccentric super-rich.

From the perspective of climate change readiness, it's almost too good to pass up. Because exponential growth is also occurring in wind and solar energy. Even IKEA is starting to sell solar panels. There is the growing source of clean energy to feed the growing number of EVs.

Conversely, the batteries in the cars themselves are just asking to be used as the storage device that is required by wind and solar energy, which fluctuates with weather and the daily rhythm. If the generation of energy is distributed over farmers' land and residents' roofs, why should the storage not be distributed? Given the right kind of smart metering, and the right financial incentive, EVs and renewable energy can rise together. We'll need it.

 

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Cars News and Reviews Natural Gas: Bridge Fuel or Dead End?- CARS NEWS AND REVIEWS

Posted by Carmella Ross on Wednesday

[NOTE added 27 February 2014: There is NO scientific evidence that a positive feedback has kicked in. While methane levels are high (and increasing), they would have to be much, much higher to trigger "runaway global warming". Scott Johnson de-bunks the claims of a "methane emergency" (and the subsequent extinction of the human race by 2035) in this well-argued post].

 

A while ago, I looked into cars that run on compressed natural gas. Natural gas is cheap. It has been touted as a "clean" source of energy - anyway cleaner than coal. The burning of natural gas does not release soot particles that post a health problem; in addition, generating energy from natural gas releases less carbon dioxide, a greenhouse gas that causes global warming.

At least, that's the argument given by proponents of hydraulic fracturing, or "fracking" of gas-containing shale. But methane (CH4), the main component of natural gas, is itself a greenhouse gas, and one that is much more potent than carbon dioxide. Its global warming potential is usually quoted as GWP=25.

What that means is that methane is 25 times more effective at trapping heat than carbon dioxide, over a period of 100 years after its release into the atmosphere: GWP(methane, 100yr) = 25.

So, if methane is really to be a "clean" (meaning low-GWP) source of energy, there had better be no leaks: not around the rigs where the fracking happens, not in the pipelines that take that natural gas to power plants and homes.

But methane does leak.

This is not the ideal world, and as any homeowner knows, sooner or later some pipe in the house will leak.

The leaks around a fracking field can be as high as 9% of the recovered methane. That's enough to make natural gas a much less "clean" fuel, in the context of global warming, than coal.

Pipelines to users, exposed as they are to varying temperatures, vibrations, aging, and other realities, leak also. A team of scientists have taken a natural gas sniffer along roads all over Boston, MA, looking for any leaks. The picture is not pretty.



Image by Kaiguang Zhao of Duke University

In the image, the height of the spikes indicate the methane concentration at that location. Yellow indicates a concentration higher than 2.5 parts per million. In Cambridge, you can see Harvard and MIT light up.

More bad news comes from the recent IPCC report on climate change, in which the global warming potential of methane has been revised: its GWP is not 25 as stated in previous IPCC reports, but actually 34. So all those leaks are having a larger contribution to global warming than previously thought.

Even that is not the end of the story.

It was recently found that if you were to suddenly increase the carbon dioxide in the atmosphere, a third to half of the resulting climate change would occur in the first ten years following the increase.

While the 100-year time horizon used for the global warming potential is appropriate for the long lifetimes of carbon dioxide and the slow but steady pace of global warming so far, it may not be appropriate if the planet ever gets into the undesirable stage of runaway global warming: in that case a 20 year time horizon would be more appropriate.

Because methane has a shorter lifetime than carbon dioxide, the 20-year GWP of methane is much larger than its 100-year GWP. The latter has also been revised up by the IPCC, from 72 to 86.

GWP(methane, 20yr) = 86

The reason this is worrisome, is that methane has its own hockey-stick, its concentration rising sharply since the beginning of the Industrial Revolution.



Image from Skeptical Science

The current methane concentration is around 1.75 parts per million. That's a lot smaller than the concentration of carbon dioxide (400 parts per million, but because the global warming potential of methane is 86 times larger, methane's radiative forcing (that is, its contribution to global warming) is already about a third that of anthropogenic carbon dioxide.

This contribution could increase greatly over the coming years, as the US is steadily shifting from coal to natural gas, and as other countries around the world, such as the UK and the Netherlands, are getting into the fracking gambit.

It's not just fracking of shales. Methane can be won from clathrates or "fire ice", a special structure of water ice with methane trapped inside. Vast deposits of clathrates are found deep in the oceans, and especially the Japanese have been interested in developing it as a substitute for nuclear energy which has recently been shown to be fraught with risk.

In addition, huge quantities of methane is trapped inside permafrost, for instance in the Siberian tundra where the subsoil remains frozen year round. If the permafrost thaws as global warming proceeds, the methane will be released from the permafrost and hasten the global warming, in a vicious cycle which scientists call positive feedback.

To see what it might mean for the future of the human race, watch "Last Hours", a video by Thom Hartmann that explores the potential threat of runaway global warming that could be triggered by the sudden release of frozen methane.



Click on image for NBC segment on methane in permafrost.

The feedback may have already begun, with the release of methane from the East Siberian Arctic shelf, following the retreat of arctic ice.

In a classroom, "positive feedback" is when your teacher pats you on the back and says "Great job!" This is not that kind of positive feedback. In the context of global warming, you want to stay away from positive feedback as far as you possibly can: the methane feedback cycle can be truly vicious.

 

 

NOTE added 8 October 2013: More Bad News For Fracking: IPCC Warns Methane Traps More Heat [than we thought]. Joe Romm's piece for the Energy Collective concurs with the above; posted 7 Oct 2013.

NOTE added 27 February 2014: There is NO scientific evidence that a positive feedback has kicked in. While methane levels are high (and increasing), they would have to be much, much higher to trigger "runaway global warming". Scott Johnson de-bunks the claims of a "methane emergency" (and the subsequent extinction of the human race by 2035) in this well-argued post.

 

 

You may also like:

1. Notes to myself on Radiative Forcing and Global Warming Potential

2. Let's Talk with Our Children about Global Warming

 



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