Photo Credit: Sergei Grits/The Associated Press via The Globe and Mail
A recent United Nations (UN) report states that a temperature increase of 1.5 degrees will be inevitable within the next few years, causing irreversible consequences and a shift from severe to disastrous impacts to ecosystems worldwide.
In December 2015, at a UN climate conference held in Paris, 195 countries reached an official agreement to control greenhouse gas emissions and confront the impacts of climate change. They agreed to hold global warming well below 2 degrees and to make efforts to limit the increase to below 1.5°C, compared to pre-industrial average temperatures.
Due to the Paris Agreement in 2015, many activists and politicians have advocated for climate justice and efforts to promote a safe climate.
Although efforts to control climate change intensified after the Paris Agreement, scientist and professor Joeri Rogelj from Imperial College London states in the UN report that years of inaction and delay resulted in the inevitable exceedance of the 1.5-degree limit.
Scientists have also been discussing the potential for an overshoot. The term “overshoot” describes a situation where temperatures exceed a set limit before declining after a period of time. Overshoots often follow four stages: exceedance, peak warming, decline, and stability. The length of an overshoot will greatly increase its effects on long-term environmental risks and harm.
“The goal is not to accept overshoots, it is to keep it as low and as short as possible.” said Mirey Atallah, Chief of the UN Environmental Programme, Adaptation and Resilience branch in a video posted to a UN YouTube account. The greater and longer an overshoot is, the greater the risks and damages.
Consequences from irreversible long-term rises in sea level, permanent loss of glaciers and species, transformation of ecosystems, and increasing risks of droughts, floods, and extreme heat will result from passing the limit of 1.5 degrees.
In early October, scientists from the National Aeronautics and Space Administration (NASA) determined that sea levels will continue to rise over centuries, even if global temperatures rise over the 1.5-degree target and then decline significantly, causing continuous and irreversible harm to biodiversity and sea levels. The NASA report shows that sea levels are expected to rise by another 10–15 centimetres by 2050, and that the rate of rise has more than doubled since 1993. Scientists have already seen its effects firsthand with the increase in ocean expansion near small islands.
According to Atallah, “Every fraction of a degree matters, every year matters, and every action matters.”
The report’s first proposal of action is the immediate reduction of global greenhouse gas emissions, in order to reach a balanced atmosphere where the amount of emissions emitted is equivalent to or less than the amount removed. Actions such as reforestation and carbon dioxide removal will determine the peak and decline of the overshoot.
Taking further steps in choosing options for the Earth is the second key to keeping the climate below the 1.5-degree mark after its overshoot decline. Scientists agree such decisions require planning ahead for uncertainties and maintaining the flexibility needed to account for inevitable impacts.
According to a UN report on limiting the overshoot, neither mitigation nor adaptation will accomplish a safe climate without justice and equity. Those located in rural areas are statistically proven to contribute the least to rising global temperatures; however, they receive most of the impacts of climate change. The report lists policies for equity and justice as a priority, specifically financial support for unavoidable loss and damage.
Listed in their latest report were the possibilities of non-linear temperature changes happening during overshoots, where the pathway of an overshoot can easily depend on ecosystems, communities, and societies at the time, and whether they can recover and regain stability quickly while reversing damage and lowering climate risks.