Climate change inaction could leave future generations facing over $500trn of debt

A global warming protest in Cleveland, Ohio, in July 2016. Image: Getty.

By continuing to delay significant reductions in greenhouse gas emissions, we risk handing young people alive today a bill of up to $535trn. This would be the cost of the “negative emissions” technologies required to remove CO₂ from the air in order to avoid dangerous climate change.

These are the main findings of research published earlier this year in Earth System Dynamics, conducted by an international team led by US climate scientist James Hansen, previously the director of NASA’s Goddard Institute for Space Studies.

The Paris Agreement in 2015 saw the international community agree to limit warming to within 2°C. The Hansen team argue that the much safer approach is to reduce atmospheric concentrations of CO₂ from the current annual average of more than 400ppm (parts per million) back to 1980s levels of 350ppm. This is a moderately more ambitious goal than the aspiration announced in Paris to further attempt to limit warming to no more than 1.5°C. Many climate scientists and policymakers believe that either the 2°C or 1.5°C limits will only be possible with negative emissions because the international community will be unable to make the required reductions in time.

Putting carbon back in the ground

The most promising negative emissions technology is BECCS – bioenergy with carbon capture and sequestration. It involves growing crops which are then burnt in power stations to generate electricity. The carbon dioxide produced is captured from the power station chimneys, compressed, and piped deep down into the Earth’s crust where it will be stored for many thousands of years. This scheme would allow us to both generate electricity and reduce the amount of CO₂ in the Earth’s atmosphere.

Other energy sources are at best carbon-neutral, but BECCS removes more than it emits. Image: creative commons.

BECCS has important limits, such as the sheer amount of land, water and fertiliser required to satisfy our energy demand. Perhaps more importantly, it doesn’t exist at anything like the scale required of it. Thus far only small pilot projects have demonstrated its feasibility. Other negative emissions approaches involve fertilising the ocean to increase photosynthesis, or direct air capture which sucks CO₂ out of the air and converts it into plastics or other products.

The Hansen team estimate how much it will cost to extract excess CO₂ with BECCS. They conclude that it would be possible to move back to 350ppm mainly with reforestation and improving soils, leaving around 50bn tonnes of CO₂ to be mopped up with negative emissions technologies (the plants grown for BECCS take in the CO₂, which is then sequestered when burned).

But that’s only if we make significant reductions in rates of emissions right now. If we delay, then future generations would need to extract over ten times more CO₂ beyond the end of this century.

Scenarios for future carbon dioxide emissions and extraction. Image: author provided.

They estimate costs between $150-350 for each tonne of carbon removed via negative emissions technologies. If global emissions are reduced by 6 per cent each year – a very challenging but not impossible scenario – then bringing CO₂ concentrations back to 350ppm would cost $8-18.5trn, spread over 80 years at $100-230bn a year.

If emissions remain flat or increase at 2 per cent a year, then total cost balloons to at least $89trin and potentially as much as $535trn. That’s $1.1trn-$6.7trn every year for eight decades.

To give these numbers some context, the entire US federal budget is about $4trn, while annual spending by all countries on military and defence is $1.7trn.

A climate balancing act

Humans have pumped over 1.5trn tonnes of CO₂ into the atmosphere since 1750. It is not just the amount, but the rate at which this CO₂ has been added. The oceans can absorb extra CO₂ but not fast enough to remove all human inputs and so it has been progressively building up in the atmosphere. This extra CO₂ traps more heat than would otherwise escape out into space. More energy is therefore entering the climate system than leaving it.


Over decades and centuries the climate will move back into balance with the same amount of energy leaving as entering. But this will be at a higher temperature with among other things less ice, higher sea levels, more heatwaves, and more floods. The last time the Earth’s climate experienced such an energy imbalance was the Eemian interglacial period some 115,000 years ago. At that time global sea levels were six to nine metres higher than today.

The Hansen team argues that even maintaining the current energy imbalance risks locking in several metres of sea level rise. That is because slow processes such as melting ice sheets still haven’t “caught up”. The longer the climate is held out of balance, the greater their effect will be.

One argument against making drastic cuts to greenhouse gas emissions is that it will harm economies as our industries are still largely fossil fuelled. Responding to climate change needs to balance the desire to continue to grow economies today with avoiding disastrous climate change or prohibitively expensive remedies tomorrow.

Whatever assumptions you make about economic growth, or however much you discount future costs, it’s unimaginable that $535trn could be afforded. While these costs will be spread over 80 years, this will also be a period in which the global population will increase from 7bn to perhaps 11bn and beyond. Humanity will need to grow enough crops to feed these billions while fuelling BECCS schemes at a time when climate change will already be impacting food production. There are also no guarantees that BECCS or any other negative emission technologies will actually work. If they fail then large amounts of CO₂ could be released very rapidly with disastrous consequences.

The ConversationBy delaying significant carbon emission reductions we risk handing both an impossible financial and technological burden to future generations. Our children and grandchildren may be unable to understand how we negotiated such an arrangement on their behalf.

James Dyke, is a lecturer in sustainability Science at the University of Southampton.

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

 
 
 
 

To beat rising temperatures, Vienna launches a network of 'Cool Streets'

A Vienna resident cools off at one of the city's new Cool Streets installations. (Courtesy Christian Fürthner/Mobilitätsagentur Wien)

Over the past several months, Austria has recorded its highest unemployment rate since World War II, thanks to the economic aftermath of the Covid-19 pandemic. With no job or a suddenly smaller income – not to mention the continued threat of the virus – many Viennese will opt for a staycation this summer.  

At the same time, last year, Austria’s capital experienced 39 days with temperatures of over 30°C (86°F), one of its hottest summers in history according to the Central Institute for Meteorology and Geodynamics.

Climate experts expect a similarly sizzling 2020 season, and city officials are now doubling down on efforts to combat the heat by launching a “Cool Streets” initiative as well as a new, state-of-the-art cooling park.

“As the city councilwoman in charge of climate, it is my job to ensure local cooling,” Vienna’s deputy mayor Birgit Hebein proclaimed at the opening of one of 22 new “Cool Streets” on 22 June.

“In Austria, there are already more heat deaths than traffic fatalities,” she added.

Hebein was referring to the 766 people the Austrian Agency for Health and Food Security included in its 2018 heat-associated mortality statistics. The number was up by 31% compared to 2017, and in contrast to the 409 people who died in traffic collisions the same year.

The project includes 18 temporary Cool Streets located across the city, plus four roads that will be redesigned permanently and designated as “Cool Streets Plus”.

“The Plus version includes the planting of trees. Brighter surfaces, which reflect less heat, replace asphalt in addition to the installation of shadow or water elements,” said Kathrin Ivancsits, spokeswoman for the city-owned bureau Mobilitätsagentur, which is coordinating the project.


Vienna's seasonal Cool Streets provide shady places to rest and are closed to cars. (Petra Loho for CityMetric)

In addition to mobile shade dispensers and seating possibilities amid more greenery provided by potted plants, each street features a steel column offering drinking water and spray cooling. The temporary Cool Streets will also remain car-free until 20 September.

A sensor in the granite base releases drinking water and pushes it through 34 nozzles whenever the outside temperature reaches 25°C (77°F) . As soon as the ambient temperature drops to 23°C (73°F), the sensor, which operates from 10 a.m. to 8 p.m., turns off the water supply.

The sensors were included in part to allay concerns about legionella, a pathogenic bacteria that can reproduce in water.  

“When the spray stops, the system drains, and therefore no microbial contamination can develop,” said Dr. Hans-Peter Hutter, deputy head of the Department of Environmental Health at the Center for Public Health at Medical University Vienna, in a televised interview.

Hutter also assured the public that there is no increased risk of a Covid-19 infection from the spray as long as people adhere to the one-meter social distance requirement.


But Samer Bagaeen of the University of Kent's School of Architecture and Planning notes that air cooling systems, like the ones used in Germany at abattoirs, have been found recently to be a risk factor for Covid-19 outbreaks.

“The same could be said for spay devices,” he warned.

Vienna’s district councils selected the 22 Cool Street locations with the help of the city’s Urban Heat Vulnerability Index. The map shows where most people suffer from heat by evaluating temperature data, green and water-related infrastructure, and demographic data.

“Urban heat islands can occur when cities replace the natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat,” as the US Environmental Protection Agency states.


A rendering of Vienna's planned park featuring a Coolspot, which is scheduled to open in August. Click to expand.
(Courtesy Carla Lo Landscape Architecture)

Vienna’s sixth district, Mariahilf, is such an area. The construction of the capital’s first “Cooling Park”, a €1 million project covering the 10,600 square-metre Esterházypark, is designed to provide relief. 

Green4Cities, a centre of excellence for green infrastructure in urban areas, designed the park’s main attraction, the “Coolspot”. The nearly 3.40-metre high steel trellis holds three rings equipped with spray nozzles. Textile shading slats, tensioned with steel cables, cover them.

The effects of evaporation and evapotranspiration create a cooler microclimate around the 30 square-metre seating area, alongside other spray spots selectively scattered across the park.

The high-pressure spray also deposits tiny droplets on plant and tree leaves, which stimulates them to sweat even more. All together, these collective measures help to cool their surroundings by up to six degrees.

The landscape architect Carla Lo and her team planned what she calls the “low-tech” park components. “Plants are an essential design element of the Cooling Park,” Lo says. “By unsealing the [soil], we can add new grass, herbaceous beds, and more climate-resistant trees to the existing cultivation”.

Light-coloured, natural stone punctuated by grass seams replaces the old concrete surfaces, and wooden benches meander throughout the park.

Living near the park and yearning for an urban escape close by, Lo says she’s motivated to ensure the park is completed by mid-August.

“If we don't do anything, Vienna will be another eight degrees Celsius hotter in 2050 than it already is,” Hebein said.

Vienna recently came in first in the World's 10 Greenest Cities Index by the consulting agency Resonance.

“There is no one size fits all on how cities respond to urban heat,” says the University of Kent’s Bagaeen, who points out that Vienna was one of the first European cities to set up an Urban Heat Islands Strategic Plan in 2015.

In the short term, prognoses on the city’s future development may be more difficult: Vienna votes this autumn.

Petra Loho is a journalist and photographer based in Austria.