Making the connection between extreme weather and climate change

Outside the supermarket today, a woman greeted me in the desperate way we have all been greeting each other this summer, whether friend or stranger; “Hot, isn’t it?” The weather report now talks not just about “mid-summer days,” but about “dangerously hot” days. In today’s 37°C heat, the woman follows up with the phrase, “It can’t be helped.” And while she is right – since experts tell us we are at the point where we cannot stop climate change, doing nothing is a horror story that we do not want to live. We are going to look at what form that story is taking on in Japan, and offer some advice on what you can do to improve it.

This mental disconnect between climate change and the extreme weather that Japan is experiencing – a prolonged rainy season, increased precipitation, heavy flooding – is occurring on a societal level. And I wonder, how long will it take Japan to start seriously discussing the link between the two? Once the impact is even more disastrous for us human beings?

We cannot afford any more time naively accepting extreme weather as something that we cannot influence. The main driver of climate change is humans’ activities, and unless we drastically change our lifestyle, the temperature will keep rising, and the number of extreme and deadly weather events will increase.

Japan is already experiencing clear effects from climate change. Based on the “Nippon Changes” report by the WWF (World Wide Fund For Nature), we look at what some of them are, and what further ones are expected in the future. The report, however, was released in 2008, and the consensus is that current climate changes are occurring faster than we had previously expected. There is no time to lose.

Japan’s climate is already hotter & more extreme

According to the WWF, over the last 100 years, the average temperature in Japan has increased by 1°C, and the number of extremely hot days with a maximum temperature higher than 35°C has increased.

The number of days with heavy precipitation, and the number of days with no precipitation, have both increased, which is why we typically experience a longer rainy season. Also, the frequency and intensity of extreme weather events, such as heavy rain, have increased, which is why flooding is occurring more frequently in Japan in recent years.

Finally, the number of days with cold temperatures, the frequency of frost, and the amount of snowfall have significantly decreased.

In short, Japan is becoming hotter, experiencing more natural disasters and extreme weather events, and having less snow. This is all part of climate change.

More extreme climate change lies ahead

Over the next 100 years, the average temperature in Japan will increase by 2°C – 3°C. Around the Sea of Okhotsk to Japan’s north, the temperature will rise by 4°C. Moreover, the number of days above 30°C will increase from 40 days to 100 days a year over the 21st century.

The number of frost days will decrease by 20 days to 45 days annually by 2090. However, mean precipitation will increase by more than 10% by 2100. Especially in summer, precipitation will increase by 17% to 19%. Such change will alter the duration of the seasons.

What and who will climate change affect?

Coastal lives

Warming temperatures are accelerating a rise in the sea level. Japan’s shoreline has risen at an annual rate of 5 mm since 1993, and it is predicted to increase even more. The global sea level will rise between 18 and 59 centimeters over the 21st century. With an average increase of 30 cm, 50% of Japan’s sandy beaches will disappear. Sea level rises also contribute to beach erosion and typhoons, and threaten coastal communities.

Increase in human diseases

Vulnerable people in Japan, particularly its sizeable elderly population, will be exposed to heat exhaustion and infectious diseases as higher temperatures encourage vector-borne and water-borne diseases. For instance, the habitat of mosquitoes is expanding in Japan and could result in the spread of diseases such as dengue fever, even to Hokkaido in the north.

Impact on agriculture and fisheries

Higher temperatures are affecting agriculture in various ways throughout Japan. In Hokkaido, the yield of rice has increased, while the yield of fruit has decreased. The IPCC predicts rice yield will drop by 40% in central to southern Japan under conditions of as much as twice the concentration of carbon dioxide in the air as currently exists. The temperature gains have already caused regions in Japan to experience grapes not turning red, and the flesh of peaches turning brown while they are still on the trees.

Higher temperatures will affect life under the sea, too, and Japan will see a reduction in some fish populations. Temperature change affects fish metabolism, growth, and distribution, which will result in a transformation of the ocean ecosystem and food chain.

Extinction of plants and animals

Climate change has already caused the extinction in Japan of more than 20% of mammals, amphibians, brackish water and freshwater fishes, and (vascular) plants, as well as reptiles. More species will become extinct in the future, while exotic and invasive species thrive, and pests and diseases will increase due to the temperature gain.

Similarly, some tree species are migrating in elevation in response to temperature change and the number of alpine plants in Hokkaido is declining. They could disappear from there altogether.

What we can do to avoid the worst climate horror story

Climate change has already been threatening ecosystems and human lives, and that will accelerate. The number of extreme weather events will increase, the agriculture and fishery sector will face decreased yield, and vulnerable populations will be exposed to the risk of climate-related diseases. Moreover, 46% of the population in Japan and 47% of the industrial output will be threatened by storms, typhoons, and coastal erosion as a result of sea-level rise.

To prevent such a catastrophic situation, we need to reduce GHG emissions to keep the temperature rise below the 2°C threshold. Ideally, each person will work to keep their own GHG emissions below 2 tons per year. There are many free online tools to keep track of your daily carbon footprint. You could start by taking a quiz at FoodPrint.

Now is the time for Japan to sit down and determine the steps it will take to curb climate change. We need to do more than just chit-chat about it – we need to take responsibility and take action.
Next time someone at the supermarket follows up a complaint about the heat or the length of the rainy season with, “It can’t be helped,” it’s time for me to say, “But it can be. Have you changed your electricity supplier to a green energy one?”

It’s long past time we faced this issue together.