Climate Explained is a collaboration between The Conversation, Stuff and the New Zealand Science Media Centre to answer your questions about climate change.
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Does reducing speed reduce emissions from the average car?
Every car has an optimal speed range that results in minimum fuel consumption, but this range differs between vehicle types, design and age.
Typically it looks like this graph below: fuel consumption rises from about 80km/h, partly because air resistance increases.
But speed is only one factor. No matter what car you are driving, you can reduce fuel consumption (and therefore emissions) by driving more smoothly.
This includes anticipating corners and avoiding sudden braking, taking the foot off the accelerator just before reaching the peak of a hill and cruising over it, and removing roof racks or bull bars and heavier items from inside when they are not needed to make the car lighter and more streamlined.
In New Zealand, EnergyWise rallies used to be run over a 1200km course around the North Island. They were designed to demonstrate how much fuel could be saved through good driving habits.
The competing drivers had to reach each destination within a certain time period. Cruising too slowly at 60-70km/h on straight roads in a 100km/h zone just to save fuel was not an option (also because driving too slowly on open roads can contribute to accidents).
The optimum average speed (for both professional and average drivers) was typically around 80km/h. The key to saving fuel was driving smoothly.
In the first rally in 2002, the Massey University entry was a brand new diesel-fuelled Volkswagen Golf (kindly loaned by VW NZ), running on 100% biodiesel made from waste animal fat (as Z Energy has been producing).
A car running on fossil diesel emits about 2.7kg of carbon dioxide per litre and a petrol car produces 2.3kg per litre. Using biofuels to displace diesel or petrol can reduce emissions by up to 90% per kilometre if the biofuel is made from animal fat from a meat works. The amount varies depending on the source of the biofuel (sugarcane, wheat, oilseed rape). And of course it would be unacceptable if biofuel crops were replacing food crops or forests.
Regardless of the car, drivers can reduce fuel consumption by 15-20% by improving driving habits alone – reducing emissions and saving money at the same time.
When you are thinking of replacing your car, taking into account fuel efficiency is another important way to save on fuel costs and reduce emissions.
Many countries, including the US, Japan, China and nations within the European Union, have had fuel efficiency standards for more than a decade. This has driven car manufacturers to design ever more fuel-efficient vehicles.
Most light-duty vehicles sold globally are subject to these standards. But Australia and New Zealand have both dragged the chain in this regard, partly because most vehicles are imported.
New Zealand also remains hesitant about introducing a “feebate” scheme, which proposes a fee on imported high-emission cars to make imported hybrids, electric cars and other efficient vehicles cheaper with a subsidy.
In New Zealand, driving an electric car results in low emissions because electricity generation is 85% renewable. In Australia, which still relies on coal-fired power, electric cars are responsible for higher emissions unless they are recharged through a local renewable electricity supply.
Fuel and electricity prices will inevitably rise. But whether we drive a petrol or electric car, we can all shield ourselves from some of those future price rises by driving more efficiently and less speedily.
Imagine a future in which every one of Australia’s 537 local government areas, including all our capital cities and major regional centres, achieve net zero greenhouse emissions. It might sound like a pipe dream, but it could be closer than you think.
A new Climate Council report, released today, tracks the climate action being taken at the local government level. It gives myriad examples of cities, towns and local shires, in Australia and abroad, setting and achieving ambitious goals for renewable energy, energy efficiency, and sustainable transport.
Meanwhile, it’s at the local government level where enthusiastic action to embrace a more sustainable future is really taking off.
For some, the inspiration for action was a pledge by more than 1,000 mayors, local representatives and community leaders to move to 100% renewable energy. The promise was made on the sidelines of the 2015 Paris climate negotiations, at an event called the Climate Summit for Local Leaders.
The International Energy Agency (IEA) has estimated that transforming the way energy is used and generated in cities and towns worldwide has the potential to deliver 70% of the total emissions reductions needed to stay on track for the 2℃ global warming limit set by the Paris Agreement. The IEA has described cities as the key to decarbonisation.
The leaders of some of Australia’s own major cities are certainly no slouches when it comes to climate aspiration:
Ambitions are also high at regional and local council levels. One in five councils surveyed by Beyond Zero Emissions indicated they were aiming for “100% renewable energy” or “zero emissions”. Examples detailed in the Climate Council report include, among others:
Yackandandah, Vic: 100% renewable energy by 2022
Lismore, NSW: 100% renewable energy by 2023
Uralla, NSW: 100% renewable energy in 5-10 years
Newstead, Qld: 100% renewable energy by 2017
Darebin, Melbourne: zero net emissions by 2020.
Power to cities
To coincide with the report, the Climate Council is also today launching its Cities Power Partnership, a free nationwide program that aims to transform Australia’s energy future from the ground up.
Thirty-five councils, representing more than 3 million Australians (12% of the population), signed up to the program even before it was launched. To join, councils identify five items in the “Power Partners pledge” that they will strive to achieve. These items include increasing the proportion of renewable energy generated within the local area; improving energy efficiency; providing sustainable transport options; building community sustainability partnerships; and engaging in climate advocacy.
Participants will then complete a six-monthly online survey on progress. In return, the Cities Power Partnership will provide incentives for councils to deliver on their selected targets and to work together to help each other. Members of the partnership will have access to a national knowledge hub and an online analytical tool to measure energy, cost and emissions savings of projects. They will also be buddied with other councils to share knowledge; receive visits from domestic and international experts; be connected to community energy groups; and be celebrated at events with other local leaders.
Ultimately, the CPP is designed to help local communities sidestep the political roadblocks at national level, and just get on with the job of implementing climate policies.
These may be only small projects when considered individually, but the idea is to link them into a network that, together, can make a big difference to one of our most significant challenges. After all, the only way to eat an elephant is to take one bite at a time.
The most comprehensive collection of atmospheric greenhouse gas measurements, published today, confirms the relentless rise in some of the most important greenhouse gases.
The data show that today’s aggregate warming effect of carbon dioxide (CO₂), methane (CH₄) and nitrous oxide (N₂O) is higher than at any time over the past 800,000 years, according to ice core records.
Building on half a century of atmospheric measurements by the international research community, we compiled and analysed the data as part of a group of international scientists, led by Malte Meinshausen from the University of Melbourne in collaboration with CSIRO.
Together, the data provide the most compelling evidence of the unprecedented perturbation of Earth’s atmosphere. They clearly show that the growth of greenhouse gases began with the onset of the industrial era around 1750, took a sharp turn upwards in the 1950s, and still continues today.
The new collection of records comes from measurements of current and archived air samples, air trapped in bubbles in ice cores, and firn (compacted snow). The data cover the past 2,000 years without gaps, and are the result of a compilation of measurements analysed by dozens of laboratories around the world, including CSIRO, the Bureau of Meteorology’s Cape Grim Station, NOAA, AGAGE and the Scripps Institution of Oceanography, among others.
These data include 43 different greenhouse gases released into the atmosphere from dozens of human activities and industrial processes. While CO₂, CH₄ and N₂O are on the rise, some other greenhouse gases such as dichlorodifluoromethane (CFC-12) are slowly starting to decline as a result of policies to ban their use.
The greenhouse gases
Most of us know that CO₂, CH₄ and N₂O are among the principal causes of human-induced climate change. They are found in the atmosphere in the absence of human activity, but the increases in their concentrations are due to human activities such as burning fossil fuels, deforestation and agriculture (livestock, rice paddies, and the use of nitrogen-based fertilisers). They are all from biological or fossil fuel sources.
But there is much more when it comes to greenhouse gases. Our analysis features a further 40 greenhouse gases (among hundreds that exist), many of them emitted in very small quantities. Although many might play a small role, dichlorodifluoromethane (CFC-12) and trichlorofluoromethane (CFC-11) are the third and fifth most important greenhouse gases respectively, in terms of their overall contributions to global warming.
Most of these gases are emitted exclusively by humans, the so-called synthetic greenhouse gases, and have been used variously as aerosol spray propellants, refrigerants, fire-extinguishing agents, and in the production of semiconductors, among other industrial applications.
Synthetic greenhouse gases include chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), most perfluorocarbons (PFCs), sulfur hexafluoride (SF₆), and others. Several, most famously CFCs, also deplete the ozone layer and are regulated under the Montreal Protocol. Others, such as HFCs, were actually first produced in large quantities to replace the ozone-depleting substances, but unfortunately turned out to be potent greenhouse gases too.
Importantly, all 43 greenhouse gases offer opportunities to tackle climate change, either by reducing their emissions or, in the case of synthetic gases, finding non-greenhouse alternatives.
Not all greenhouse gases are the same
How much a greenhouse gas contributes to warming depends on three factors. The first is how much gas is emitted. Second is how much a kilogram of that gas will warm the planet once it’s in the atmosphere. And third is how long the gas will remain in the atmosphere.
CO₂ is the most important greenhouse gas in warming the planet, despite being the weakest greenhouse gas per unit of mass. Its contribution to warming comes from the sheer scale of emissions (40 billion tonnes emitted each year), and the fact that a large part effectively hangs around in the atmosphere for hundreds or thousands of years after emission. The resulting concentration makes CO₂ responsible for about 65% of all warming due to greenhouse gas emissions from human activities.
This makes CO₂ the most important factor in determining future global warming. Unless we can cut CO₂ emissions to zero by the second half of this century, primarily by finding alternatives to fossil fuels, the world will continue to warm beyond the 2℃ target of the Paris Agreement, not to mention the aspirational 1.5℃ goal.
Methane (CH₄) is the next most important greenhouse gas, with current concentration contributing about 15% of overall human-induced warming.
Most synthetic greenhouse gases have very high global warming potentials. The one with the highest current emissions is the refrigerant HFC-134a, which is 1,300 times more potent than CO₂ (per mass unit emitted). Other synthetic greenhouse gases have even more extraordinary warming potentials, with CF₄ (used in the semiconductor industry) and SF₆ (from industrial electricity transformers) being 6,500 and 23,400 times more potent than CO₂, respectively.
CFC-12, a former refrigerant, is both a potent ozone-depleting substance and a powerful greenhouse gas. Although its emissions and atmospheric concentrations are now declining thanks to global compliance with the Montreal Protocol, it is still the third most important greenhouse gas and responsible for 6-7% of all warming since the beginning of the industrial era.
What are these GHG data good for?
Our new compilation of greenhouse gas data is the most complete and robust picture to date showing the main drivers of climate change, and how we humans are altering the Earth’s atmosphere. Global temperature is now about 1℃ warmer on average than pre-industrial temperatures.
The new database also serves as an accurate measure of greenhouse gas concentrations resulting from past human and natural emissions, which will in turn help to improve the performance of climate models. Building trust and confidence in climate projections starts by testing and running models with real data during historical periods. The new climate projections will feed in the next major report from the Intergovernmental Panel on Climate Change, due to be released in 2021.
Continued greenhouse gas monitoring, including significant contributions by Australia, is crucial to understand how the planet reacts to human interference, and to better plan for adaptation to a changing climate. Global and regional greenhouse data can help nations to track the long-term global targets under the Paris agreement, and to inform actions needed to stabilise the climate.
It is now day 5 of the road trip and I have already covered almost 3000km. As you can appreciate covering that amount of territory in 5 days doesn’t leave a lot of time to Blog, especially when I have been trying to keep the website updated as well.
What I thought I might do in this Blog is just pass on a few thoughts that have come to me while I have been driving around this great state of Australia – New South Wales. Let’s call this post, ‘A Few Thoughts From the Road.’
I have often thought that the governments of this country are wasting a great opportunity in promoting tourism in Australia. With such great distances to travel in Australia, wouldn’t it be great if the governments came up with an action plan to improve the rest areas throughout the country. Certainly some of them have been upgraded to a wonderful state – but then there is a lack of maintenance.
Many of the rest areas I have stopped at in the last few days have no facilities at all. Often they are nothing more than an overloaded garbage bin on the side of a road, with limited space in which to park.
To cut a long story short, I think Australia’s tourism industry would get a great shot in the arm if rest areas were improved across the country. It would also be good if hey could be located somewhere with a good view, an attraction, a small park for families, etc.
To go a step further (and this is perhaps pie in the sky), wouldn’t it also be great for the many Australians that drive throughout the country on camping/caravan holidays, if a percentage of these rest areas had some limited facilities for tents and caravans as well?
Perhaps a lot more people would travel around the country if such improved rest areas were created. There would also need to be some plan to keep the maintenance of these areas up to scratch also.
Another thing that militates against the travelling tourism that is fairly popular in Australia (it could be far greater), is the condition of many of the caravan parks across the country. To be sure, there are some excellent parks – but there are also a large number of parks that charge top dollar for run down facilities and grubby grounds. These poor operators need to lift their games to provide good facilities for their customers or they won’t get the return business that caravan parks depend upon. They need to spend a bit of money in order to make money.
I won’t return to a caravan park in which I had a bad experience – whether it be top dollar for run down facilities, poor service, poor attitudes of operators, etc. Some of these places just have no idea how to run a successful caravan park.
The planning for my holiday is now well and truly underway, with the holiday now being referred to as my ‘NSW Road Trip 2010.’ There is also a website address for viewing my itinerary and for following my progress. It has been a rushed process in the end, organising this road trip, so there will yet be some changes to the itinerary.
I am expecting changes in far western NSW due to road conditions, especially given recent weather conditions out that way, including the widespread rain and flooding that has taken place. Given I have only got a small rental for this trip, I am not really prepared to take the car onto certain roads (which I believe will be part of the rental agreement anyway).
At this stage I am expecting to miss Ivanhoe and head for Mildura instead. I also expect to miss Tibooburra in the far northwest corner of the state, as the Silver City Highway is largely dirt. With these probable changes to the itinerary, I will also miss driving through the Menindee Lakes area, which really was something I was hoping to see – another time perhaps.
On another ‘track,’ I found our that the hottest February temperature experienced in Ivanhoe was around 48 degrees Celsius. No, not the reason I am thinking of bypassing Ivanhoe – most centres out west have similar temperatures in February anyway.