It’s Not Enough, Scientists Say of World’s Greenhouse Gas Policies

(CN) — New research indicates that simply reducing greenhouse gas emissions is not enough to avoid the massive costs and environmental destruction that young people are likely to face if the effects of climate change compound and worsen.

Nations must aim for negative emissions, according to a study published Tuesday in the journal Earth System Dynamics.

While reforestation and other measures to remove carbon dioxide from the atmosphere will help, elevated fossil fuel emissions will require costly technological solutions to extract additional CO2 and prevent dangerous warming.

“Continued high fossil fuel emissions would saddle young people with a massive, expensive cleanup problem and growing deleterious climate impacts, which should provide incentive and obligation for governments to alter energy policies without further delay,” said lead author James Hansen, a professor at Columbia University.

Without rapid restraints on greenhouse gas emissions, environmental impacts could include floods and droughts, frequent and extreme heat waves, and sea level rise.

“Sea level rise this century of say half a meter to a meter (1.6 to 3.3 feet), which may be inevitable even if emissions decline, would have dire consequences; yet these are dwarfed by the humanitarian and economic disasters that would accompany sea level rise of several meters,” the scientists wrote.

Hansen, former head of the NASA Goddard Institute for Space Studies in New York City, said that atmospheric CO2 should be reduced to fewer than 350 parts per million from the current level of about 400 ppm. To do so, nations must reduce CO2 emissions by 6 percent a year by 2021, and extract roughly 165 gigatons of carbon from the atmosphere by 2100. A gigaton is 1 billion tons.

Most carbon in the atmosphere can be removed through improved forestry and agricultural practices alone, which would be comparatively inexpensive, and could enhance forest products and soil fertility.

However, if CO2 emissions grow at a rate of 2 percent a year — they rose 2.6 percent a year from 2000 to 2015 — nations would need to extract more than 1,100 gigatons of carbon from the atmosphere by 2100. This could be achieved only by using expensive technological solutions, according to the team.

Bioenergy achieved through carbon capture and storage is one such costly measure that could be used if reduction efforts are not implemented in a timely fashion, or to a sufficient level. This process captures and stores CO2 in geological formations under airtight rock. The team estimates this technology could cost up to $535 trillion and would present “large risks and uncertain feasibility.”

The research is a part of the scientific basis for legal action in Juliana et al. v. United States, filed in Eugene, Oregon Federal Court in 2015 by 21 young people, claiming the president and major government agencies are violating their constitutional rights to life, liberty and property by failing to address climate change.

“We wanted to quantify the burden that is being left for young people, to support not only the legal case against the U.S. government, but also many other cases that can be brought against other governments,” Hansen said.

The team said that even if global average temperatures stay below 1.5 degrees Celsius (2.7 degrees Fahrenheit) above pre-industrial levels — the primary goal of the 2015 Paris climate agreement — climate feedbacks could be “slowed,” possibly leading to the partial melting of ice sheets and resulting sea level rise.

“It is apparent that governments are leaving this problem on the shoulders of young people,” Hansen said. “This will not be easy or inexpensive.”

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