Climate Policy

The economic and emissions benefits of engineered wood products in a low-carbon future

The 195 signatories of the Paris Agreement on climate change have committed to reduce greenhouse gas (GHG) emissions so as to keep the global temperature rise from preindustrial levels to well below two degrees Celsius (2°C). While much of this international effort has focused on the economy’s two largest-emitting sectors, electricity and transportation, achieving net-zero emissions will require emissions reductions in all sectors of the economy. That includes construction.

Among the most difficult emissions to reduce are cement and steel, which are primarily used as building materials. One potential solution is to substitute for these materials with engineered wood products, which are less GHG-intensive and have seen rapid growth in the construction industry in recent decades. This study evaluates the economy-wide impacts of replacing carbon-intensive construction inputs, such as steel and cement, with lumber products in the U.S. under an emissions constraint. It’s one of the few studies to examine the emission and economic impacts of these products under a climate policy.

Drawing upon their U.S. economy database, the researchers determined that the carbon dioxide (CO2) intensity of lumber production is about 20 percent less than that of fabricated metal products, under 50 percent that of iron and steel, and under 25 percent that of cement. They found that the ability to substitute lumber-based building materials increases production from the lumber and forestry sectors and decreases production from carbon-intensive sectors such as cement. Under a carbon cap-and-trade policy, the ability to substitute lumber products lowers the carbon price and the GDP cost of meeting the carbon cap, with more overall emissions abatement in the construction industry.

Even “modest” action to limit climate change could help prevent the most extreme water-shortage scenarios facing Asia by the year 2050, according to a new study led by MIT researchers.

The study takes an inventive approach to modeling the effects of both climate change and economic growth on the world’s most heavily populated continent. Roughly 60 percent of the global population lives in Asia, often with limited access to water: There is less than half the amount of freshwater available per inhabitant in Asia, compared to the global average.

Study: Climate action can limit Asia’s growing water shortages

When the Paris Agreement was launched in 2015, nearly 200 nations pledged to enact and continually strengthen policies aimed at keeping the rise in global average surface temperature since pre-industrial times to well below two degrees Celsius. Meeting that ambitious goal will require a dramatic decarbonization of the world’s energy system over the course of the 21st century. Critical to this collective effort will be the deployment of low-carbon energy sources at a very large scale.

Charting the future of decarbonization
The Impact of Climate Change Policy on the Risk of Water Stress in Southern and Eastern Asia

In March 2016 a team of MIT Joint Program researchers published a study in PLOS One that found a high risk of severe water stress in Asia by 2050. An MIT News article on that study led to several stories in media outlets, from CNBC to Voice of America. Since that study was published, the same research team has been working to assess the extent to which climate mitigation and adaptation practices could reduce the future risk of water stress in a region that’s home to 60 percent of the world’s population. Reducing that risk could both save lives and help ensure sustainable growth in the area.

In a paper accepted by Environmental Research Letters, the team focused on the impact of climate change on the risk of water stress in Southern and Eastern Asia (SEA) by midcentury, and how climate mitigation could lower that risk.

Using models that link climate, hydrology, socio-economics and water management, they produced large ensemble projections of future water supplies and use in response to scenarios of climate change and socioeconomic growth by midcentury. These large ensembles were needed in order to capture all plausible outcomes in the regional and global patterns of future climate and socio-economic change. The researchers examined the most likely outcomes of these projections as well as what could occur at the extremes (low-probability cases). They found that while population and economic growth contributes to increased risk of water stress (water-use near or exceeding supply) across the region, unconstrained climate change enhances that risk in China and reduces it in India. They also noted that in the most extreme cases, climate change results in a severe increase in water stress in both nations, where annual freshwater use would routinely exceed supply.   

To evaluate the potential benefit of climate mitigation on water-stress risk throughout the SEA region, the research team considered a large-ensemble scenario under a modest reduction in greenhouse gas emissions (comparable to the current COP21 international agreement). They found that the avoided climate changes eliminate the likelihood of the extreme outcomes described above. Furthermore, the researchers projected that the policy would reduce the additional population (since the year 2000) in the SEA region under threat of facing at least heavily water-stressed conditions from climate change and socioeconomic growth from 200 million to 140 million—a 30-percent decrease.  

Yet even with mitigation, the researchers estimated that there’s a 50 percent chance that 100 million people across the SEA region will experience a 50 percent increase in water stress and a 10 percent chance they will experience a doubling of water stress by 2050. The team maintained that to address these unavoidable risks, SEA nations will ultimately need to implement widespread adaptive measures. And that will be the subject of the researchers’ next study.

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