Solar cars designed specifically to race in competitions such as the North American Solar Challenge or the Green Global Challenge (previously the World Solar Challenge) must somehow move at freeway speeds with less power than a typical hairdryer. Building these vehicles is a grand exercise in energy efficient design, and demonstrates what’s possible when engineers focus on producing maximum results with very limited power consumption. This is the third installment in a series that discusses several strategies solar car designers use to squeeze the most performance out of a vehicle-sized solar array. As with the larger energy system that powers our homes, vehicles, and factories, the best solution is not necessarily to focus only on producing more (ideally renewable) power, but also to identify and eliminate waste in systems that use energy. Designing for energy efficiency is a very cost-effective strategy to addressing energy problems.
One significant source of energy consumption in cars is tire rolling resistance. Basically, it takes some amount of force to roll a tire forward, even if you are not accelerating or going uphill. A simplified model of rolling resistance is:
This equation describes how much force is required to roll a tire forward at a constant speed on a flat road; this force is called rolling resistance . It depends on two things: the vertical load supported by the tire (i.e., the normal force ), and the coefficient of rolling resistance . The normal force depends on how weight is distributed in your car, and the rolling resistance is a function of tire design (and is also influenced by things like temperature, speed, and tire slip). Rolling resistance goes up proportionately with both normal force and with . We would like to reduce rolling resistance in order to reduce the energy consumed while driving. It’s easy to see that one way to do this is to reduce how much a car weighs, which reduces . Suppose we’ve eliminated as much vehicle mass as possible, and still want to reduce rolling resistance further. How do we reduce ? To understand this, let’s have a look at where rolling resistance comes from.
When rubber tires roll over the road they deform. The spot that touches the road (the contact patch) is flattened just a little due to the force of the car pushing down. Imagine what happens to one piece of rubber in your tire as the tire rolls on the ground. Looking at the drawing below, at position 1, the piece of rubber is slightly curved. As the tire rolls, the piece of rubber moves into position 2, and it starts to deform. By the time it gets to position 3, it’s pretty much flat, and then as it moves through position 4 to position 5, it returns to its original shape.
All the rubber in the tire tread and sidewalls goes through some type of deformation with each revolution of the tire. It takes energy to deform rubber. We get most of that energy back when the rubber ’springs’ back into shape. But rubber is not exactly like a spring; you don’t get back all the energy you put into it. Rubber is what we call viscoelastic. The elastic part of viscoelastic is the springy part. Something has elastic behavior if it springs back into shape after being deformed. The viscous part means that when something is deformed, energy is lost, and resistance to deformation increases with how fast you try to deform it. Think of stirring a pot of honey; if you stir it slowly it doesn’t take much effort, but if you try to stir it fast the viscosity of the honey makes it harder to stir. Where does all the energy go from stirring? The honey doesn’t ’spring back’, so you can’t recover the energy like you can with a spring. The energy from stirring was converted to heat; the honey became a little bit warmer.
Tires exhibit both viscous and elastic behavior. Some of the energy is recovered when the rubber springs back into shape after rolling through the contact patch (point 3). Due to the viscous nature of rubber, there is extra resistance to deformation, as well as resistance to returning to its normal shape. The energy used to overcome this extra resistance is converted to heat; bending rubber back and forth makes it heat up (sort of like stirring the honey). Have you ever noticed how tires get warm after driving? The energy that warms your tires is energy lost. How can we minimize this lost energy (and reduce rolling resistance)? There are three main approaches:
Reduce tire deformation: if tire rubber is deformed less, then less energy will be consumed. This can be accomplished by increasing tire pressure (one important reason to make sure your tires are inflated properly). It’s important not to over-inflate tires, however, as this could degrade handling and ride quality, compromise safety, and accelerate tire wear. Tire deformation can also be reduced by adjusting tire design, that is, changing its shape and what it’s made of.
Reduce how much tire is deformed: narrower tires and tires with thinner tread have less rubber that moves in and out of the contact patch, reducing how much energy is lost from tire deformation. There are tradeoffs, however. Narrow tires may not handle as well, and thinner tread reduces durability.
Reduce rubber ‘viscosity’: using a harder rubber compound can help shift tire behavior closer to purely elastic, meaning that a greater proportion of energy that goes into deforming rubber is elastically recovered. Again, there is a tradeoff. Harder rubber compounds may not grip the road as well as softer compounds.
Some tire manufactures have created tire specifically for solar cars, with emphasis on ultra-low rolling resistance. Solar car tires are thin, high-pressure tires with hard rubber compounds. They have rolling resistance coefficients as low as 0.0025, whereas high efficiency passenger car tires have coefficients near 0.006, and typical passenger car and light truck tires have coefficients much higher than that. To give you a sense of the legendary efficiency of solar car tires, I was contacted by engineers interested in using solar car tires on bicycles they were developing for breaking human-powered speed records. Solar car tires are more efficient than racing bicycle tires.
Below is a photo of a solar car tire along with a view of the suspension (this is a photo of the Stanford solar car from several years ago). Notice the electric hub motor just to the right of the wheel. There is a direct connection between electric motor and wheel; no drive shafts, gears, belts or chains to sap energy.
The next photo shows a pile of solar car tires. Since these tires are optimized for energy efficiency, they don’t last very long. They must be replaced frequently, and it takes a large pile of tires to make it through a long cross-country solar car race.
Solar car tires are intended for specialized racing vehicles, and are obviously impractical for passenger vehicle applications. Nevertheless, we can take lessons from their design to help improve efficiency of production vehicles. Maybe we could move toward higher pressure tires, and use more advanced suspension design to help counteract the harsher ride from stiffer, high pressure tires. As we make other vehicle aspects more efficient (such as aerodynamics or powertrain design), the energy lost through rolling resistance will become an increasingly important factor, and is an opportunity for improvement.
Last summer Americans had a taste of high fuel prices, and our driving habits and vehicle choices actually started to change. Substantially higher prices certainly would cause a lot of pain, particularly in the short term, but what benefits might we realize? Chris Steiner, Forbes columnist and author of$20 Per Gallon: How the Inevitable Rise in the Price of Gasoline Will Change Our Lives for the Better, explained in a recent NPR interview that dramatically higher prices could lead to a better way of living.
Steiner predicts that as fuel prices climb, we will become less of a disposable society, and migrate to denser, more interactive living arrangements. Air travel may not be economically viable for most of us, and travel by rail will grow in popularity (look at nations in Europe or Asia with high-speed rail infrastructure for examples). Other positive changes include more exercise in people-centered (as opposed to car-centered) communities, cleaner air, better (local) food, and improved health. And let’s not forget one of my favorite impacts: increased popularity of cycling.
In addition to environmental and health benefits, curbing petroleum consumption is a national security issue. This video features retired generals and others discussing a recent report from CNA that ‘explores the impact of America’s energy choices on our national security policies’. Vice Admiral Richard Truly, USN (Ret.), discussed the urgency of helping improve public knowledge about energy use, and the importance of resolving our energy situation. General Chuck Wald, USAF (Ret.), explained that Americans must realize that our energy situation is not going to take care of itself without us being a part of it. The link to national security alone could be motivation enough to take action.
The transition to higher fuel prices and lower consumption will certainly be painful, and hurt more for certain segments of the population than others. Should we wait for fuel prices to rise due to market forces and adapt then, or should we take some preemptive action to ease the transition? A phased-in fuel tax could be used to fund required infrastructure changes, as well as investments in technology that will enable us to enjoy a high standard of living on far less petroleum. Revenues could also be used to assist those struggling most with the transition to higher fuel prices. Instituting a U.S. fuel tax would funnel revenue into infrastructure and investments that benefit Americans, whereas waiting for market forces to drive up fuel prices will instead boost revenue for oil producers. Automakers actually support a fuel tax, hoping that it will stabilize fuel prices so they can invest in advanced technologies with more confidence in future demand for energy efficient vehicles. The main question here is not whether fuel prices will increase, but would we rather transition with foresight and a strategy, or just wait until we are forced into reacting. The former option would certainly be less painful, and would leave us in a much better position after the transition.
A strategic transition would require a substantial fuel tax (or a price floor), but this appears to be politically impossible right now. What do you think it would take for U.S. citizens to support an appropriate fuel tax?
When you hear someone is an engineer, what is your first thought? Are these poor souls cursed with “The Knack”?
Or, does something else come to mind? There is a lot of talk about technological solutions to energy and other sustainability problems, but who actually makes all of this happen? We need policy makers to create an environment conducive to investment, innovation, and implementation, but we also need creative people who have a grounded understanding of how to make things work (i.e., engineers).
When I was at the IESS Conference last month, I heard Chuck Vest, president of the National Academy of Engineering, speak of the concerning state of engineering education in the U.S. (you can download his slides here). He explained that the graduation rate for engineering in the U.S. is lagging substantially, which “does not bode well for our future”. He described the 14 Grand Challenges for Engineering (a topic for another article), which is a set of critical problems facing our world that require engineering solutions. We need more engineers to tackle these challenges, several of which involve sustainability and energy issues.
Chuck Vest spoke of studies that aimed at understanding why so few Americans pursue engineering as a profession. One question that was asked of college students in these studies was “why aren’t you studying engineering?”. A popular response was “because I want to make the world better”. Clearly this is a failure in communication; engineers can have a profound positive impact on the world and create lasting value. Why is there a disconnect? Why don’t our youth see engineering as a way to make our world better? What can we do to inspire more Americans to become part of the technological solution so that we can build a better future and reestablish America’s leadership role in science and engineering? Have a look at this video and this post for a few ideas.
Vest proclaimed that we must get the word Engineer back into the vernacular. Engineering needs to be a more common topic of conversation. We need to somehow remake the perception of engineers. I believe this requires action on two fronts. Obviously we need to get the public more interested and excited about engineering, not just absorbed with enjoying the fruits of engineering. In addition, perhaps we need to adjust what engineering is. For example, a common theme at IESS was to address problems holistically, not just from a narrow disciplinary view. We can’t just design technical solutions in a bubble, ignoring relationships with other aspects of the world. The problems we are facing are growing too complex to continue with that approach. We need renaissance engineers: people who are skilled in more than one discipline. We need engineers who can focus on solving important societal problems, and who are willing to learn about and engage with other disciplines outside engineering (e.g., economics, psychology, public policy, etc.). Taking a whole-systems approach to solving these socio-technical problems will lead to much better solutions, and perhaps will improve public perception of engineering and it’s role in improving the world.
Paul Krugman, Professor of Economics at Princeton, summarizes what the passing of the Waxman-Markey bill would mean to Americans in a short NPR interview. He explains how it will help us take into account the cost of global warming into the economy, providing incentives to change how we produce and consume energy (see my article on externalities for more on this). He says that the overall number of jobs will remain about the same, but the mix of jobs will be different. Krugman says he would bet his Nobel prize that the climate bill would not cost Americans much financially (he says serious studies conclude it would cost most families less than the value of a postage stamp per day), but was not willing to bet his Nobel prize that the bill would save the world, explaining that it may not be enough. In fact, some members of Congress opposed the bill because they felt it was not aggressive enough. Several environmental groups, including Greenpeace, also oppose the bill for the same reason.
How does all of this relate to design? While many exciting technologies are emerging that help us use less energy and produce it more sustainably, these technologies only make it to market if they make economic sense. To invest in a new renewable energy project, for example, a business case must be made. If we include the true, long-term costs of fossil fuel derived energy, some renewable energy sources are clearly the right choice. While many engineers and others are concerned about sustainability and interested in energy efficiency and renewable energy, this concern is not enough to produce the large-scale shift to sustainability we need. We need to create an economic environment that supports substantial, continued investment that will accelerate the development and deployment of clean energy technology.
I hear many folks talking about what individual choices they can make to reduce their carbon footprint or live more responsibly. I hear support for wind and solar energy. Consumers are starting to consider ‘greenness’ in purchasing decisions. But oft times there seems to be a disconnect when it comes to making collective choices that will bring about substantial change, much more than what individual choices will procure. We need to shift our collective support from status quo energy systems to new energy strategies that will carry us (and the natural world) through successfully for generations to come. The innovative spirit and talent is there, waiting to rise to the challenge. It will lie relatively dormant until citizens make the clarion call for strong incentives and bold policy that will empower engineers and others to accelerate the metamorphosis of our energy, transportation, and agricultural systems.
Waxman-Markey is not ideal. It may not be enough. But perhaps it will give Americans a taste of the exciting progress that can be made when we focus and guide our efforts in the right direction. Perhaps after this first taste we will be willing to move beyond this first step.
The Waxman-Markey bill may not be the ideal solution, but its passing is a landmark event, and offers significant progress over the status quo. This energy/climate change/jobs bill passed the House hours ago by a narrow margin; it still needs to pass the Senate. Friday’s vote is historic, and deserves increased attention. If you are looking for a way to have a big personal impact on sustainability, consider learning and talking about this and other legislation that is aimed at leading society toward a path of sustainabilty and better quality of life for the long term.
Please welcome the newest Design Impact guest blogger: Sterling Anderson. Sterling is a Ph.D. student at MIT working in the Robotic Mobility Group. In today’s article, Sterling writes about his work in the next generation of vehicle stability and hazard avoidance control, and how it relates to vehicle sustainability.
Today I’d like to briefly discuss exciting new developments in a field not commonly associated with or considered a critical component of vehicle sustainability. That field is vehicle safety. The connection I’d like to draw between safety and sustainability goes as follows: no matter what its energy source (gas, hybrid, electric, etc), a vehicle may be made more efficient by removing or otherwise lightening its structural elements. Many of these elements, however, such as secure seat belt harnesses, large airbag systems, sturdy roll cages, and large crumple zones, cannot be removed without increasing the risk of injury to vehicle occupants in the event of a collision. This limits the degree to which vehicles can be made smaller (which reduces drag), and lighter (less mass) without forfeiting the structural protection provided by larger and more massive vehicles.
Enter driver assistance systems. In recent years, the historical focus on passenger safety in human-controlled motor vehicles has shifted from collision mitigation systems such as seat belts, airbags, roll cages, and crumple zones to collision avoidance systems, which include anti-lock brakes, yaw stability control, roll stability control, and traction control. Whereas collision mitigation systems seek to reduce the effects of collisions on passengers, active collision avoidance systems seek to prepare for and avoid accidents altogether. This accident avoidance reduces – and may one day eliminate – the additional mass and design constraints required by passive safety systems.
But while existing collision avoidance systems are effective at reducing accident frequency, they are still limited in one respect: their avoidance methods are fundamentally “reactive” in nature. In the majority of these systems, controller intervention is based solely on current vehicle conditions, and thus cannot anticipate and prepare for future threats. For example, an anti-lock brake system seeks to help the driver avoid accidents by more intelligently applying his intended braking command – it does not preview the road ahead and decide to apply the brakes of its own accord. Ditto with stability and traction controllers; neither preemptively seeks to avoid hazards – each simply responds to the driver’s command. Thus, a drowsy, distracted, or otherwise inattentive driver receives very little benefit from such a system as it does not engage until he begins his own evasive maneuver.
Recent developments in onboard sensing (cameras, radar, laser-based sensing, vehicle-to-vehicle communication, etc.) and drive-by-wire technology have facilitated the development of collision avoidance systems that use information about the vehicle’s surroundings, along with predictive computer models to determine the best course of action to avoid an accident. If needed, such systems intervene and share steering and/or braking control with the driver. These “predictive” systems generally attempt to honor driver intentions, opposing them only when doing otherwise would lead to a collision or loss of control. By constantly monitoring a vehicle’s surroundings and predicting a safe path through them, they may warn the driver and take control of the vehicle steering and/or braking to avoid accidents before it is too late. Much like a copilot or driving instructor, this controller intervention should strike a necessary balance between the level and frequency of intervention: not altering the driver’s steering and braking inputs “too much”, “too soon”, or “too often” while still guaranteeing that the vehicle avoid hazards independent of that driver input.
In my work with MIT’s Robotic Mobility Group, we are currently developing a predictive active safety system that predicts the “best-case” trajectory through the environment, assesses the threat this trajectory poses, and intervenes as necessary to avoid accidents. We’ve tested this system in both simulation and experiment with excellent results. As the patent is still pending, I’ll defer details until my next post. Until then, you can see a demonstration of its performance in a few simulation videos posted here. In the mean time, and before I’ve biased your creativity with our solution, please brainstorm your own possible solutions. We have the technology to identify hazardous conditions and help the driver avoid collisions. What would you think of driving a car with a system like this? How do we know when intervention is “too much” or “too soon”? Feel free to discuss these ideas with others via the comment section below.
I spent the last several days at the Second International Engineering Systems Symposium, a conference involving people from a wide variety of disciplines who are working to solve difficult problems using a holistic approach. Many issues we face today are remarkably complex, and if we take a narrow view when addressing them we could run into problems. While we need experts with deep knowledge in very specific topics, we also need people who can think about systems as a whole, and how parts of a system interact with each other (sometimes producing surprising results). Some topics discussed this week include energy, climate change, health care, education, design, and the economy. I could probably write daily posts for months about this conference and still have plenty of material left. I will highlight some themes, projects, and ideas over the course of several posts that I found inspiring or important (in no particular order of importance). Today I want to point your attention to a phenomenal project taking place on a few small islands in the North Atlantic.
MIT Portugal is collaborating with numerous partners to develop and implement new energy systems for islands in the Azores, a Portuguese archipelago. What a challenging and amazing opportunity! These islands are becoming, in effect, a laboratory for researchers studying technology, public policy, economic, and other aspects of a next-generation energy system. Instead of putting a laboratory in a University, they are putting the University in the laboratory. While the needs and resources of these islands are certainly unique, they are serving as a testbed and example for the rest of the world regarding renewable energy, energy efficiency, and a holistic approach to redesigning how a society creates and uses energy. You can learn more about the Green Islands Project here, here or here.
So what is so exciting about focusing on a complete island? Think about trying to do the same thing with a city in the middle of the U.S. It is tightly interconnected with other cities through roads, power lines, rivers, etc. Numerous interactions with the world outside the city would make research results more difficult to interpret. An island has limited interactions, so in some ways it is close to being a closed system. This makes it easier for researchers to make conclusions about the changes to the energy system and the influence of these changes on the rest of the island. This research may lead to a better fundamental understanding of the next generation of energy systems, along with the socio-technical complexities that exist because of the interface between energy, social, political, economic, and environmental systems.
In the second installment of this series on ultra-efficient vehicle design, I cover briefly the aerodynamic design of solar cars and the related opportunity for significant improvement of production passenger cars.
Air resistance is very important consideration for solar cars, or any vehicle that travels at high speeds, since the power to overcome air drag increases cubically with speed. In other words, if you double your speed, the power required to overcome air resistance increases by a factor of EIGHT.
I’m going to jump right into an equation that will help illustrate some of the main concepts in this article. The force of air pushing back on a moving car, the aerodynamic drag force (), can be approximated by this formula:
where is the density of air, is the drag coefficient, is the car’s frontal area, and is the car’s velocity (speed). This equation is a simple engineering model (see my ongoing series of articles on modeling) that helps us understand how changing vehicle design and operating conditions affects aerodynamic drag force. Looking at this equation, we can see that drag force increases quadratically with speed (that is, doubling your speed increases drag force by a factor of four), and increases proportionately with frontal area and drag coefficient. Based on this equation, what can we do to reduce drag force? Obviously the most effective thing to do is reduce speed. This is why freeway speed limits were reduced to 55 mph years ago to save fuel. Let’s assume for now that the speed we want to drive our car at is fixed. What else can we do to reduce drag force? We can’t do much about reducing air density (), but we can control frontal area () and drag coefficient (). In my last post on solar car design, I explained that solar cars must make do with very limited amounts of power (less than what a hairdrier consumes). Reducing frontal area and the drag coefficient can bring solar car designers one step closer to building a car that can travel at highway speeds with only the power from the sun.
In the past, solar car racing rules allowed drivers to pretty much lie down in the car, making it possible to design cars with a very small frontal area. This really helps reduce air resistance (cyclists understand very well the importance of keeping a small profile), but makes getting in and out of the car fairly challenging. Current solar racing rules now require a more upright driver position, resulting cars that are a little closer to what commuters might consider driving. Some teams have even built two-person solar cars. While somewhat more practical, solar cars with upright seating have increased frontal area and increased air resistance.
So what about the drag coefficient? Vehicle designers can adjust the shape of the car so that air flows around it smoothly, requiring less force to push the car through the air. Solar cars are perhaps the most streamlined road going vehicles. They have smooth surfaces that taper toward the rear, ensuring that air flows over them in a smooth, laminar way. The blunt rear edge of most cars leads to a lot more air resistance, as opposed to the trailing edge of a solar car or the the Aptera 2e. Have a look at these simulation results that show how air flows smoothly over the University of Waterloo solar car without much disturbance:
The streamlined shape slices through the air without generating a turbulent wake at its tapered rear edge, in contrast to many production vehicle with blunt rear ends. Solar cars have acheived drag coefficients as low as 0.10, while the Prius sports a much larger and less efficient drag coefficient of 0.26 (which is actually the lowest of any production car). Referring to our drag equation above, that means if a Prius and a solar car had the same frontal area, the Prius would take 2.6 times as much force to overcome air resistance as the solar car at a given speed. Most production cars have noticeably higher drag coefficients; a Civic’s is 0.36, and a Hummer H2’s is 0.57. The image below illustrates how other vehicle shapes can lead to turbulent wakes, which increases a car’s drag coefficient:
While reducing drag coefficient is a paramount consideration in solar car design, it is not the only consideration. Goro Tamai, a past MIT solar car team member, discusses in his book, The Leading Edge, that aerodynamic design must be considered as a component as the overall vehicle system.
The “best” body shape for solar cars, HPVs, or Electrathoners is not the body of absolute lowest drag. The vehicle system, including the driver, chassis, and energy/drive system must work in concert to produce the maximum output.
In addition to minimizing drag, designers must ensure vehicle stability and safety, and that aerodynamic design works in concert with powertrain and power production systems to acheive the best overall vehicle performance. In the case of a solar racer, the measure of ‘best performance’ is how fast the car can safely travel a set route, powered only by the sun. I’ll explore the importance of systems engineering in vehicle design in a later article in this series.
So how do these ideas transfer to production vehicle design? First of all, the low drag coefficient of solar cars compared to production cars is astounding. Clearly low drag is not a top priority in production vehicles; there is tremendous room for improvement. Solar cars illustrate what is possible, and give some insights into how to do it (smaller frontal area, tapered rear edge, smooth undersides, and wheels covered by fairings, for example). Spencer Quong, a senior vehicle analyst with the Union of Concerned Scientists, has explained that solar car development “opens the industry’s eyes to how to build a more efficient vehicle.”
A recent article from allcarselectric.com claims that the new Honda Insight looks so much like the Prius because when you optimize a vehicle for aerodynamics, you converge on something that looks like the Prius. Considering our discussion above, the shape of the Prius clearly is not aerodynamically optimal. It’s good, but it’s possible to do much better. I suspect that marketing and visual cues are much bigger factors here than truly slippery shapes. Prius styling is becoming a symbol of ‘green’, its shape now spark thoughts of energy efficiency. If the objective was to minimize drag, I contend that designers would arrive at a vehicle shape closer to the Aptera 2e.
An auto manufacturer obviously needs to build cars that people want to buy. They need to perform well and look good. We have the ability to improve performance and energy efficiency of production cars by moving toward more streamlined shapes, but would many people buy these cars? What do you think could be done to shift public perception and preference such that genuinely low-drag vehicles could become marketable? This is an important question; developing demand for vehicles with dramatically lower drag would have considerable impact on energy consumption.
A team of students from Ohio State University took first place at the 2009 EcoCAR Challenge today. Here is an excerpt from the press release:
The Ohio State University took first place out of 17 universities in the U.S. and Canada that competed in the first major milestone of this three-year competition which is sponsored by the U.S. Department of Energy, General Motors, and many others including the Government of Canada. The competition challenges university engineering students across North America to re-engineer a 2009 Saturn VUE to improve fuel efficiency and reduce emissions while retaining the vehicle’s performance and consumer appeal. …
The winning team’s EREV provides a practical solution that will increase energy efficiency and reduce environmental impacts. The Ohio State’s design was powered by a 1.8 litre engine and fueled by E85 ethanol. The next-generation design predicts a 300 per cent increase in fuel economy over the production 4 cylinder vehicle.
In case you didn’t know, today is World Environment Day. Here is a blurb from the UNEP website:
World Environment Day (WED) was established by the UN General Assembly in 1972 to mark the opening of the Stockholm Conference on the Human Environment.
Commemorated yearly on 5 June, WED is one of the principal vehicles through which the United Nations stimulates worldwide awareness of the environment and enhances political attention and action. The day’s agenda is to:
Give a human face to environmental issues;
Empower people to become active agents of sustainable and equitable development;
Promote an understanding that communities are pivotal to changing attitudes towards environmental issues;
Advocate partnership which will ensure all nations and peoples enjoy a safer and more prosperous future.
The theme for WED 2009 is ‘Your Planet Needs You-UNite to Combat Climate Change’. It reflects the urgency for nations to agree on a new deal at the crucial climate convention meeting in Copenhagen some 180 days later in the year, and the links with overcoming poverty and improved management of forests.
This year’s host is Mexico which reflects the growing role of the Latin American country in the fight against climate change, including its growing participation in the carbon markets.
Mexico is also a leading partner in UNEP’s Billion Tree Campaign. The country, with the support of its President and people, has spearheaded the pledging and planting of some 25 per cent of the trees under the campaign. Accounting for around 1.5 per cent of global greenhouse gas emissions, the country is demonstrating its commitment to climate change on several fronts.
Mexican President Felipe Calderon states that the WED celebration will “further underline Mexico’s determination to manage natural resources and deal with the most demanding challenge of the 21st century – climate change.”
Earth Day is certainly more well-known that WED. I like the comments above on helping people become ‘active agents of sustainable and equitable development’, and the need to unify to have the sort of impact that we need. The impact of individual green decisions can be noticeable, but what we really need is the synergistic effect of a unified effort. See my post on Earth Decade for some more thoughts on this topic.
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