Climate change follows the law of physics

by AKM Saiful Islam | Updated at 11:33pm on November 12, 2016

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Hoesung Lee, left, chair of the Intergovernmental Panel on Climate Change, UN climate chief Patricia Espinosa, second from left, COP22 president Salaheddine Mezouar, centre, attend the opening session of the COP22 climate talks in Marrakesh on November 7. — Agence France-Presse/Fadel Senna

THIS week representatives from 197 parties who signed the Paris Agreement are meeting at Marrakesh for the 22nd Conference of Parties (COP22). As of November 5, 103 parties have ratified, accepted and approved the Paris Agreement which now becomes an internal law. The central focus of the Paris Agreement is to strengthen the global initiatives to keep the global rise in temperature by the end of this century well below 2 degrees Celsius above pre-industrial levels and pursue efforts to limit even further to 1.5 degrees Celsius. It is, therefore, important to understand why the rise in temperature of additional one and half a degrees is matter for us. Secondly, what types of measures are required to achieve these targets? Finally, what are the additional benefits by limiting the global warming level below 1.5°C compared with 2°C? As a research scientist working in this field, I have made an attempt to explain these issues based on the available scientific information published in articles and reports.

How realistic is the 1.5°C goal?
LIMITING the warming level below 1.5°C is still feasible. Based on the climate projections of low emission scenarios (representative concentration pathways, RCP 2.6), a few models show that the warming level will peak to 1.5°C by mid-century before slowly declining to below this level. However, it will require aggressive mitigation actions beyond the intended nationally deterministic contributions that all countries of the United Nations Framework Convention on Climate Change are currently planning.

What types of measures would be required?
EVERY country should follow a pathway of sustainable low carbon-emission energy. Green energy is consisted of energy conservation, sustainable energy and sustainable transport of energy. Energy conservation includes efficient energy use, green buildings, heat pump and low-carbon power, etc.
Sustainable energy includes renewable energy such as hydropower, solar energy, wind energy, geothermal energy, bioenergy and tidal energy, etc. Sustainable transport includes carbon-neutral fuel, electric vehicles, fossil fuel phase-out, green vehicle plug-in hybrid, etc. Additionally, research is ongoing to achieve net zero emission by the end of this century.
Programmes such as reducing emissions from deforestation and forest degradation and bio-energy can help to reach for a greener future. Bio-energy with carbon capture and storage is a future greenhouse gas mitigation technology which produces negative carbon dioxide emissions by combining bioenergy (energy from biomass) use with geologic carbon capture and storage. For example, recent studies showed that algae or cyanobacteria offer a natural mechanism to convert solar energy into a fuel is one of them.

Is focus on the 1.5°C goal distract from the well-below 2°C goal?
NOT really. The world will be safer if we able to keep global increase of temperature well below 1.5°C from the pre-industrial period. The Paris Agreement put into force on November 4, 2016 aims to make the efforts to limit the temperature increase to 1.54°C above pre-industrial levels by recognising the need to avoid the risks and irreversible negative impacts of climate change. Climate-vulnerable countries such as the least developed countries (such as Bangladesh) and the small island developing states would be able to suffer less if we are able to limit temperature increase below 1.54°C warming level.

Difference between climate change impacts of 1.54°C and 244°C
MANY studies are ongoing to detect the adverse impact would going to be happened between 1.5°C and 2°C. A recent study of Oxford University revealed that the probability of extreme events such as floods, droughts, storms and heatwave would increase in a 2°C world. Tropical coral reefs which already under stress because of high ocean temperature would get a chance for adapting under 1.5°C. However, tropical corals will be virtually wiped out by 2100 in a 2°C world. An extra half a degree would reduce 50 per cent of the corn yields in some parts of Africa. Warming below 1.5°C would save the Amazon rainforest and Siberian tundra from melting and releasing dangerous methane. By the end of this century, the sea level rise would be additionally 10cm between 1.5°C and 2°C world. Sea level rise is already threatening many small island countries and flat deltas such as Bangladesh. In many regions of the Mediterranean which is suffering from drying, the availability of fresh water resources would be about 10 per cent lower in a 1.5°C world compared with 17 per cent lower in a 2°C world. Therefore, it is clear that tropical regions which are known for mostly developing countries that are already highly vulnerable to climate change will face the biggest challenges if global warming rise between 1.5°C and 2°C.
Finally, climate change is a nearly invisible threat which follows nothing but the law of physics. Therefore, it is time to stand up to save our planet, time to save ourselves, and time to save the humanity!

AKM Saiful Islam is a professor of the Institute of Water and Flood Management at the Bangladesh University of Engineering and Technology.