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Three simple reasons why climate change is real, and humans are causing it

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David Waltham, reader in mathematical geology at Royal Holloway, lays out three compelling reasons why climate change is real – and it is manmade.

This article was originally published on the Conversation. Read the original here.

Dire warnings of imminent human-induced climate disaster are constantly in the news but predictions of the end of the world have been made throughout history and have never yet come true. Even in the brief period of recorded history, natural climate change has always been with us – whether it is the volcanically induced crop failures that helped precipitate the French revolution or the medieval warm period that allowed Vikings to colonise Greenland. So how can we trust that the computer models scientists use to make predictions are reliable?

There is sometimes reluctance to take experts’ words for anything and so we would like to be shown the evidence. Unfortunately, that is difficult when the details are buried under hundreds of thousands of lines of computer code which implement mathematical algorithms of mind-numbing complexity. There is, however, one branch of science that can reliably give an answer that is easy to understand and hard not to believe.

1. Evidence written in stone

Paleoclimatology – the study of Earth’s past climates – has used fossils to show links between global temperatures and carbon dioxide levels. This record is written in stone. There are fossil plant leaves from 55m years ago that have a microscopic structure which can be accurately reproduced in modern plants only when grown in a carbon dioxide-rich atmosphere. Is it a coincidence that, at the time, it was so warm that crocodiles were living within the Arctic circle?

And this is not an isolated case. A sedimentary record covering half a billion years shows us exactly what we would expect to see if climate modellers have done their sums right. Fossil and chemical traces in rocks indicate that warm periods in Earth’s history are associated with higher concentrations of carbon dioxide and quantitative studies show that this correlation is, if anything, even stronger than predicted.

2. Simple calculations

Those 55m year-old leaves suggest that carbon dioxide concentrations were about four times the present day levels and back-of-the-envelope calculations indicate that global mean temperatures were around 7C higher. For comparison, the largely computer-based predictions published by the Intergovernmental Panel on Climate Change (IPCC) imply that quadrupling carbon dioxide concentrations should increase temperatures by between 3C and 9C.

The simple paleoclimate example may not nail the case for a worryingly strong link between carbon dioxide and temperature, but it is good supporting data. What is most important, however, is that this evidence is hard to refute

3. Counter arguments are unconvincing

There is little doubt that the recent rapid increase in carbon dioxide is linked to human activities such as burning of fossil fuels and deforestation. But does the paleoclimate evidence really tell us that increased carbon dioxide must mean increased temperatures?

One objection might be that ancient climate change is really evidence for varying solar brightness. Fluctuating carbon dioxide levels are then a response to climate variation rather than the cause. However, solar physics tells us that the sun was fainter 55m years ago rather than brighter, as would be needed for higher temperature.

Another concern is that some important processes, such as ice sheet disintegration, only affect climate very slowly. Our warming ice sheets may take centuries to disappear completely but, when they do, the replacement of reflective ice by heat-absorbing rock will warm our planet yet further. The existence of potential complications like these makes comparisons between paleoclimate change and modern climate change difficult but it is also one of the reasons why multiple approaches are needed. If different researchers using different methods nevertheless come up with more or less the same answer, perhaps they are onto something.

Climate change deniers also confuse the argument by suggesting there is nothing we can do anyway. China and other rapidly developing countries will dominate carbon dioxide output in the 21st century. But that is irrelevant if we are simply asking: “Will increased carbon dioxide levels change our climate?

The fact that political and technical problems are massively more complex than anything in climatology is not a reason to stick our heads in the sand. Widespread agreement that manmade global warming is highly likely would be progress.

Next, read this: Establishing consensus on climate change is vital for actionThe Conversation.

David Waltham does not work for, consult to, own shares in or receive funding from any company or organisation that would benefit from this article, and has no relevant affiliations. This article was originally published on the Conversation. Read the original here.

Photo: Makio Kusahara via freeimages

Further reading:

Climate scientists ‘95% sure’ that global warming is manmade, says leaked IPCC document

97% of scientists agree that climate change is human-caused

Why climate deniers have no scientific credibility – in one pie chart

Just one of 2,258 scientific papers rejected manmade global warming in 2013

The Guide to Climate Change 2013

Economy

Will Self-Driving Cars Be Better for the Environment?

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self-driving cars for green environment
Shutterstock Licensed Photo - By Zapp2Photo | https://www.shutterstock.com/g/zapp2photo

Technologists, engineers, lawmakers, and the general public have been excitedly debating about the merits of self-driving cars for the past several years, as companies like Waymo and Uber race to get the first fully autonomous vehicles on the market. Largely, the concerns have been about safety and ethics; is a self-driving car really capable of eliminating the human errors responsible for the majority of vehicular accidents? And if so, who’s responsible for programming life-or-death decisions, and who’s held liable in the event of an accident?

But while these questions continue being debated, protecting people on an individual level, it’s worth posing a different question: how will self-driving cars impact the environment?

The Big Picture

The Department of Energy attempted to answer this question in clear terms, using scientific research and existing data sets to project the short-term and long-term environmental impact that self-driving vehicles could have. Its findings? The emergence of self-driving vehicles could essentially go either way; it could reduce energy consumption in transportation by as much as 90 percent, or increase it by more than 200 percent.

That’s a margin of error so wide it might as well be a total guess, but there are too many unknown variables to form a solid conclusion. There are many ways autonomous vehicles could influence our energy consumption and environmental impact, and they could go well or poorly, depending on how they’re adopted.

Driver Reduction?

One of the big selling points of autonomous vehicles is their capacity to reduce the total number of vehicles—and human drivers—on the road. If you’re able to carpool to work in a self-driving vehicle, or rely on autonomous public transportation, you’ll spend far less time, money, and energy on your own car. The convenience and efficiency of autonomous vehicles would therefore reduce the total miles driven, and significantly reduce carbon emissions.

There’s a flip side to this argument, however. If autonomous vehicles are far more convenient and less expensive than previous means of travel, it could be an incentive for people to travel more frequently, or drive to more destinations they’d otherwise avoid. In this case, the total miles driven could actually increase with the rise of self-driving cars.

As an added consideration, the increase or decrease in drivers on the road could result in more or fewer vehicle collisions, respectively—especially in the early days of autonomous vehicle adoption, when so many human drivers are still on the road. Car accident injury cases, therefore, would become far more complicated, and the roads could be temporarily less safe.

Deadheading

Deadheading is a term used in trucking and ridesharing to refer to miles driven with an empty load. Assume for a moment that there’s a fleet of self-driving vehicles available to pick people up and carry them to their destinations. It’s a convenient service, but by necessity, these vehicles will spend at least some of their time driving without passengers, whether it’s spent waiting to pick someone up or en route to their location. The increase in miles from deadheading could nullify the potential benefits of people driving fewer total miles, or add to the damage done by their increased mileage.

Make and Model of Car

Much will also depend on the types of cars equipped to be self-driving. For example, Waymo recently launched a wave of self-driving hybrid minivans, capable of getting far better mileage than a gas-only vehicle. If the majority of self-driving cars are electric or hybrids, the environmental impact will be much lower than if they’re converted from existing vehicles. Good emissions ratings are also important here.

On the other hand, the increased demand for autonomous vehicles could put more pressure on factory production, and make older cars obsolete. In that case, the gas mileage savings could be counteracted by the increased environmental impact of factory production.

The Bottom Line

Right now, there are too many unanswered questions to make a confident determination whether self-driving vehicles will help or harm the environment. Will we start driving more, or less? How will they handle dead time? What kind of models are going to be on the road?

Engineers and the general public are in complete control of how this develops in the near future. Hopefully, we’ll be able to see all the safety benefits of having autonomous vehicles on the road, but without any of the extra environmental impact to deal with.

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Economy

New Zealand to Switch to Fully Renewable Energy by 2035

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renewable energy policy
Shutterstock Licensed Photo - By Eviart / https://www.shutterstock.com/g/adrian825

New Zealand’s prime minister-elect Jacinda Ardern is already taking steps towards reducing the country’s carbon footprint. She signed a coalition deal with NZ First in October, aiming to generate 100% of the country’s energy from renewable sources by 2035.

New Zealand is already one of the greenest countries in the world, sourcing over 80% of its energy for its 4.7 million people from renewable resources like hydroelectric, geothermal and wind. The majority of its electricity comes from hydro-power, which generated 60% of the country’s energy in 2016. Last winter, renewable generation peaked at 93%.

Now, Ardern is taking on the challenge of eliminating New Zealand’s remaining use of fossil fuels. One of the biggest obstacles will be filling in the gap left by hydropower sources during dry conditions. When lake levels drop, the country relies on gas and coal to provide energy. Eliminating fossil fuels will require finding an alternative source to avoid spikes in energy costs during droughts.

Business NZ’s executive director John Carnegie told Bloomberg he believes Ardern needs to balance her goals with affordability, stating, “It’s completely appropriate to have a focus on reducing carbon emissions, but there needs to be an open and transparent public conversation about the policies and how they are delivered.”

The coalition deal outlined a few steps towards achieving this, including investing more in solar, which currently only provides 0.1% of the country’s energy. Ardern’s plans also include switching the electricity grid to renewable energy, investing more funds into rail transport, and switching all government vehicles to green fuel within a decade.

Zero net emissions by 2050

Beyond powering the country’s electricity grid with 100% green energy, Ardern also wants to reach zero net emissions by 2050. This ambitious goal is very much in line with her focus on climate change throughout the course of her campaign. Environmental issues were one of her top priorities from the start, which increased her appeal with young voters and helped her become one of the youngest world leaders at only 37.

Reaching zero net emissions would require overcoming challenging issues like eliminating fossil fuels in vehicles. Ardern hasn’t outlined a plan for reaching this goal, but has suggested creating an independent commission to aid in the transition to a lower carbon economy.

She also set a goal of doubling the number of trees the country plants per year to 100 million, a goal she says is “absolutely achievable” using land that is marginal for farming animals.

Greenpeace New Zealand climate and energy campaigner Amanda Larsson believes that phasing out fossil fuels should be a priority for the new prime minister. She says that in order to reach zero net emissions, Ardern “must prioritize closing down coal, putting a moratorium on new fossil fuel plants, building more wind infrastructure, and opening the playing field for household and community solar.”

A worldwide shift to renewable energy

Addressing climate change is becoming more of a priority around the world and many governments are assessing how they can reduce their reliance on fossil fuels and switch to environmentally-friendly energy sources. Sustainable energy is becoming an increasingly profitable industry, giving companies more of an incentive to invest.

Ardern isn’t alone in her climate concerns, as other prominent world leaders like Justin Trudeau and Emmanuel Macron have made renewable energy a focus of their campaigns. She isn’t the first to set ambitious goals, either. Sweden and Norway share New Zealand’s goal of net zero emissions by 2045 and 2030, respectively.

Scotland already sources more than half of its electricity from renewable sources and aims to fully transition by 2020, while France announced plans in September to stop fossil fuel production by 2040. This would make it the first country to do so, and the first to end the sale of gasoline and diesel vehicles.

Many parts of the world still rely heavily on coal, but if these countries are successful in phasing out fossil fuels and transitioning to renewable resources, it could serve as a turning point. As other world leaders see that switching to sustainable energy is possible – and profitable – it could be the start of a worldwide shift towards environmentally-friendly energy.

Sources: https://www.bloomberg.com/news/articles/2017-11-06/green-dream-risks-energy-security-as-kiwis-aim-for-zero-carbon

https://www.reuters.com/article/us-france-hydrocarbons/france-plans-to-end-oil-and-gas-production-by-2040-idUSKCN1BH1AQ

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