The Climate Emergency: 2020 Review

 

There is mounting evidence linking extreme weather frequency and intensity to climate change. 2020 was one of the hottest years on record which saw extraordinary wildfire activity in the Western United States and Australia, a Siberian heat wave with high temperatures exceeding 38 degrees Celsius within the Arctic circle, a record low for October Artic sea ice extent, of 2.04 million square miles, an Atlantic hurricane season resulting in more than $46 billion in damage, and floods and landslides in South Asia that displaced over 12 million people.

 

Efforts must continue to reduce emissions and increase removals of atmospheric carbon. Scientists now find that catastrophic climate change could render a significant portion of the Earth uninhabitable consequent to continued high emissions, self-reinforcing climate feedback loops and looming tipping points.

 

In recent developments, The European Union is on track to meet its emissions reduction goal for 2020 and become zero net carbon by 2050; however, this goal will still increase temperatures from the damaging levels of today. Other governments are committing to zero net carbon, including China by 2060 and Japan by 2050. Similar pledges have been made by the UK, many others, although there is evidence that a 2050 or later target may be inadequate and net zero carbon should be reached much earlier. US President Joe Biden has pledged that the US will re-join the Paris Agreement and has proposed a $2 trillion climate plan to phase down fossil fuels by expanding renewable energy capacity amongst other measures. Progress for nature came in the form of the Bonn Challenge to restore forest and other ecosystems.

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Forests help to stabilise the climate

 

Forests are one of the most important solutions to addressing the effects of climate change. They regulate ecosystems, protect biodiversity, play an integral part in the carbon cycle, support livelihoods, and can help drive sustainable growth. Approximately 2.6 billion tonnes of carbon dioxide, one-third of the CO2 released from burning fossil fuels, is absorbed by forests every year. Halting the loss and degradation of natural systems and promoting their restoration have the potential to contribute over one-third of the total climate change mitigation scientists say is required by 2030.  Restoring 350 million hectares of degraded land could sequester up to 1.7 giga tonnes of carbon dioxide equivalent annually.   Estimates show that nearly two billion hectares of degraded land across the world – an area the size of South America – offer opportunities for restoration. Increasing and maintaining forests is therefore an essential solution to climate change.

 

Other benefits in support of both people and nature are considerable: Globally, 1.6 billion people (nearly 25% of the world’s population) rely on forests for their livelihoods. Forests provide US$ 75–100 billion per year in goods and services such as clean water and healthy soils; Forests are home to 80% of the world’s terrestrial biodiversity.

 

Today, more and more consumers are demanding forest products from sustainable sources, and an increasing number of major palm oil, timber, paper and other forest product corporations are beginning the conversion to deforestation-free supply chains. In addition to creating and maintaining protected areas and launching initiatives towards more sustainable management, many countries, subnational governments and private landowners are restoring degraded and deforested land.

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Could wooden buildings be a solution to climate change?

 

Trees absorb carbon. Building with timber means taking CO2 from the atmosphere and storing it in the built environment. Sustainably grown wood is an endlessly renewable and natural resource. Needing little more than sunlight and rainfall to grow, producing timber requires significantly less energy than any other mainstream building material. For example, producing steel requires 24 times the energy needed to produce wood; while concrete can give off 140kg CO2 per cubic metre produced. Moreover, as they grow, trees are producing the oxygen we breathe – almost three quarters of a tonne of oxygen for every cubic metre’s growth.

 

Using wood as an alternative to other materials saves on average 0.9 tonnes of CO2 per cubic metre. Wood also has the best thermal insulation properties of any mainstream construction material; five times better than concrete, 10 times better than brick and 350 times better than steel. This is because wood’s low thermal mass means that it has very limited ability to conduct either heat or cold, meaning that using timber in buildings makes them more easily able to retain heat.

 

Wood from managed forestry actually stores carbon as opposed to emitting it: as trees grow, they absorb CO2 from the atmosphere. As a rule of thumb, a cubic metre of wood contains around a tonne of CO2 (more or less, depending on the species of tree). Not only does wood remove more CO2 from the atmosphere than it adds through manufacture, but by replacing carbon-intensive materials such as concrete or steel it doubles its contribution to lowering CO2. A recent advisory report to the UK government on the uses of “Biomass in a low-carbon economy” found that, “the greatest levels of [greenhouse gas] abatement from biomass currently occur when wood is used as a construction material to both store carbon and displace high carbon cement, brick and steel. Between 15% and 28% of new homes built in the UK annually use timber frame construction, capturing over one million tonnes of CO2 a year as a result. Increasing the use of timber in construction could triple that amount, the report concluded. Savings of a similar magnitude may also be possible in the commercial and industrial sectors by utilising new-engineered wood systems such as cross-laminated timber (CLT).

 

CLT is the primary material on the construction site. Because it’s described as an “engineered wood” CLT just looks like ordinary 3m (10ft) planks of wood. The ingenuity is that the planks are made stronger by gluing them in layers of three, with each layer perpendicular to the other. This means that the CLT doesn’t bow or bend, it has integral strength in two directions, a CLT wall supports the floor above, with a horizontal strength to carry a load above it, acting like a long beam.

 

Many CLT factories in Austria are powered by renewable biomass. Some factories also produce enough electricity to power the surrounding communities. In certain regions CLT has the potential to reduce wildfire risk as well as supporting rural economic development and local employment. The US is investing in domestic CLT manufacturing, with factories in Montana and Oregon, and more planned in Maine, Utah, Illinois, Texas, Washington State, Alabama and Arkansas. Structures using wooden materials also tend to be quicker and easier to build, therefore reducing labour costs, transport fuel and on-site energy use. Other countries are turning to timber, too.

 

Data suggests that 1,000 cubic metres of CLT equates to around 500 harvested trees; factories processing 50,000 cubic metres are therefore trapping the sequestered carbon of 25,000 trees per year. There is also the “end of life” question. Carbon only remains trapped in the wood for as long as the building remains standing or is reused in another building – if it rots or is burned for energy, then all the stored carbon is released. Previous research work by Arup in 2014 estimated that half of all construction timber ends up in landfill, 36% is recycled and the remaining 14% burnt for biomass energy. Despite these issues, the average lifetime of a building is 50-60 years.

 

Mass adoption of CLT is an important weapon in the fight against climate change. “Could we realistically return to wood as our primary building material? “It’s not only realistic, it’s imperative, and it has to happen. In architecture you always go back to the sketch: the sketch is climate change.

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