The deadly floods and storms that increasingly batter population centers in Japan and elsewhere as well as the epic forest fires enveloping swaths of territory in Australia embody the devastating impact of human-induced climate change.
Yet, policymakers in the leading emitting countries — China, the United States, India, Russia and Japan — show no urgency to reverse climate change, as evidenced by the collapse of the COP 25 climate summit in Madrid at the end of last year.
In these circumstances, better public understanding about the climate-disaster link could swing public opinion in favor of urgent action.
That is the significance of a new article providing evidence on the link between climate change and the rising incidence of extreme floods, storms, heat waves and droughts across the world. The article is “Impacts of Carbon Dioxide Emissions on Global Intense Hydrometeorological Disasters,” by myself, Ramon E. Lopez and Pablo A. Troncoso. It appears in the January edition of Climate, Disaster and Development Journal, January 2020.
This research delineates the main contributors to the increase in the frequency of intense hydrometeorological events, specifically floods and storms. It shows how the atmospheric carbon dioxide accumulation and associated changes in climatic patterns are contributing to the increased frequency of these events worldwide.
This investigation adopts an economic approach on climate data from 155 countries over 46 years (1970 to 2016). The data bring out the very high risks faced by countries like Japan, Australia and Bangladesh. The analysis is conducted within a framework that includes socio-economic factors, in other words, people’s exposure to the hazards and their vulnerability to them.
The findings show that in addition to people’s exposure and vulnerability, climate change is contributing to turning hazards of nature into disasters. The continuous rise in atmospheric carbon dioxide concentration is significantly correlated with the increase in the number of extreme floods and storms. That means human actions have a decisive role in climate change. The results show that global climate conditions significantly affect the frequency of these disasters.
The results suggest that if the carbon dioxide level increases by 1 percent, floods and storms would increase by nearly 9 percent. The yearly increase in atmospheric carbon dioxide has been about 2.4 parts per million, or about 0.6 percent from the base 396.5 ppm level for 2010 to 2016. Accordingly, the number of intense hydrometeorological disasters could increase by 5.4 percent annually for an “average” country facing annually nearly one extreme disaster (defined as one that causes 100 or more fatalities and/or affects 1,000 or more people). So, with the current trends in carbon dioxide accumulation, the number of intense floods and storms could double (i.e., one more extreme event) in a span of 13 years.
The average annual number of extreme floods and storms in Japan is twice that of the “average” country. Extreme weather events have been more frequent in recent years. For example, Typhoon Hagibis, Japan’s largest storm in decades, battered the country’s northeast in October. Only a month before that, Typhoon Faxai hit the Kanto region, triggering massive blackouts in Chiba Prefecture. And the list goes on.
The crucial question is the link between anthropogenic climate change and the uptick in these extreme floods and storms as well as heat waves in Japan. The paper’s findings make clear that there is a strong and meaningful link between the rise in carbon emissions in the atmosphere and the increasing incidence of these extreme events, and Japan is part of this phenomenon. All indications are that this climate impact on lives and livelihoods in Japan will worsen in the coming years.
This link between the incidence of natural calamities and increase in atmospheric carbon dioxide has implications for environmental and economic policies. Rather than reacting to events as one-off and unpredictable occurrences, human-made events call for investments in prevention and mitigation programs. Our finding that the number of intense hydrometeorological disasters could double in 13 years under current trends calls for far greater investments in disaster risk reduction and mitigation.
The global evidence in this study, together with the attribution of specific disasters to climate change in the growing literature, are grounds for far stronger climate policies in Japan. Current efforts fall far short of what is needed, and this must be reversed.
On the one side, there needs to be far greater climate adaptation, such as relocating people from highly exposed regions, building better coastal defenses and enforcing building codes and retrofitting buildings.
Equally, there is a strong case for investing substantially and urgently in decarbonizing the Japanese economy. Japan is the fifth-biggest contributor to the world’s greenhouse gas emissions, and it is in the country’s and global interest to scale this back dramatically. The goal should be to end the dependency on coal and achieve a net zero carbon emission for the country well before 2050.