June 2020 has been unusually cool and wet.
The Meteorological Service Singapore (MSS) confirmed that it was the wettest June in 10 years.
While it is unusual, MSS said that the currently available research information cannot "definitively attribute" this abnormality to global warming, natural climate variability, or other effects including urbanisation.
The sweater weather is also expected to last a while more.
A climatologist from the National University of Singapore, Department of Geography, Matthias Roth, told CNA that the rainy weather is likely to continue into July.
Cooler weather still part of 'natural variability'
Roth, however, also said the cooler weather in June is part of natural variability.
He attributed the afternoon showers in June to strong solar heating at Earth's surface.
Sumatra Squalls and converging winds contributed to more rainfall in the month as well.
As the rainy weather persists in July, there is also a higher likelihood of flash floods in low-lying areas, Roth warned.
Associate Professor at Singapore University of Social Sciences, Koh Tieh-Yong, also suggested that the rainy weather can persist in the region if the La Nina phenomenon forms in the latter part of 2020, CNA reported.
A La Niña phenomenon occurs when the sea surface temperatures fall below average across the east-central Equatorial Pacific. It usually happens a year after its counterpart El Niño happened.
El Niño represents the periods when the sea surface temperatures are above the norm.
There is a 50 per cent chance for La Niña to form in the second half of the year.
Rainfall in June 2020 not extraordinary
Associate professor at Singapore Management University, Winston Chow, also weighed in with his observations.
So this @ChannelNewsAsia piece came out yesterday on Singapore's very wet & cool June 2020 - it needs some clarification because there's some confusion on whether it's "natural variation" vs. climate change. (1/10)https://t.co/Sg3rQ9nOd2— Winston Chow (周祥龙) 🇸🇬 (@winstontlchow) July 15, 2020
Chow clarified that MSS compared the record of rainfall in June over a span of 10 years' data, which is insufficient to conclude that this is a sign of climate change.
Chow plotted out the rainfall trend over 40 years from 1980 to 2020 and it does not show that the June 2020 rainfall is "extraordinary".
As you can see from his graph, there are higher rainfalls in the year 1984, 1996 and 2010, for example, even though the total rainfall for June at 233.8mm did stand out as one of the highest numbers.
Further, the important point is the MSS brief only referred to the past 10 years. I downloaded the entire Changi weather station dataset for June 1980-2020, which is available here - https://t.co/jrCnDsutWt and plotted the total monthly June rainfall...(7/10) pic.twitter.com/aYvlOdQfoP— Winston Chow (周祥龙) 🇸🇬 (@winstontlchow) July 15, 2020
So does not mean that climate change is not a thing? No.
Before we explain why climate change is still a real concern, let's get to the basics first:
Difference between climate and weather
Weather refers to a short term change in atmospheric conditions.
Climate refers to a long term change, usually looking at the averages of weather conditions in a specific area over 30 years.
Chow described the difference between climate and weather this way:
"As I tell my students - weather is your mood, climate is your personality."
Climate change still an imminent crisis
While not all extreme weathers are a sign of climate change, there is a "strong climate change" signal from the rising temperatures in the long-term record, Chow said in his 10-parter Twitter thread.
To be absolutely clear - A strong climate change signal for *temperature* exists in the long term record via shift of prob distr functions of climate anomalies. It's not the case for precipitation yet - see Figs 1,2 & 3 in this paper (open access) https://t.co/HFJR5l8LH7 (10/10)— Winston Chow (周祥龙) 🇸🇬 (@winstontlchow) July 15, 2020
A Special Report on Global Warming of 1.5°C published by the Intergovernmental Panel on Climate Change (IPCC) in 2018, which involved contributions from thousands of climate scientists and government reviewers, already stated that we are experiencing the consequences of 1°C of global warming through more extreme weather, rising sea levels, and diminishing Arctic sea ice, among other changes.
Climate change is therefore an "unequivocal" emergency that requires "unprecedented" changes in all aspects of the society to limit the warming to 1.5°C by 2100.
Singapore, being a small island state, is definitely not spared from the impacts of climate change as we experience an increase in the average temperature and sea-level rise in the recent 40 years or so.
According to the National Climate Change Secretariat (NCCS), the annual mean temperature has increased from 26.6°C to 27.7°C over 42 years from 1972 to 2014.
The mean sea level in the Straits of Singapore has also increased at the rate of 1.2mm to 1.7mm per year between 1975 and 2009.
Top photo by Zheng Zhangxin.