The United Nations IPCC = "Intergovernmental Panel on Climate Change" made up of scientists from around the world has published a report on global warming for the first time in eight years.
As global warming progresses, the frequency and intensity of "extreme phenomena" such as heat waves and heavy rains will increase, and we are warning to reduce greenhouse gas emissions.
At a meeting held online from the 26th of last month, the IPCC compiled a report on the current state and forecast of global warming based on the latest research results for the first time in eight years, and released it on the afternoon of the 9th of Japan time.
The Paris Agreement, an international framework adopted in 2015, has set the goal of keeping the average global temperature rise to 1.5 degrees Celsius compared to before the Industrial Revolution. So, the average global temperature for the last 10 years has already risen by 1.09 degrees Celsius.
On top of that, even if global greenhouse gas emissions could be reduced to virtually zero around 2050, the chances of a temperature rise of 1.5 degrees by 2040 would exceed 50%. I'm predicting.
He pointed out that as global warming progresses, the frequency and intensity of "extreme phenomena" such as heat waves and heavy rains will increase around the world.
The frequency of high temperatures observed once every 50 years is now 4.8 times that of the latter half of the 19th century before the Industrial Revolution, and when the average temperature rises by 1.5 degrees, it rises by 8.6 times and 2 degrees. If you do, it is estimated that it will be 13.9 times.
The frequency of heavy rainfall once every 10 years is currently 1.3 times, but it is predicted that if the average temperature rises by 1.5 degrees, it will increase by 1.5 times, and if it rises by 2 degrees, it will increase by 1.7 times.
The IPCC report has a great influence on international warming countermeasures, and its influence on the discussion of the UN conference "COP26" scheduled to be held in the United Kingdom in November is noteworthy.
Assessed to be the cause of global warming due to human activity
A major feature of this report is that it was the first IPCC to conclude that the cause of global warming was human activity.
Since the publication of its first report in 1990, the IPCC has gradually strengthened its expression of the impact of human activity on global warming, and eight years ago in its fifth report, "Major Warming". The factor is very likely to be human influence. "
In this report, we went further and stated that "there is no doubt that human influences have warmed the atmosphere, ocean and land," and this was the first expression to conclude.
The reason is that the rapid temperature rise observed since the Industrial Revolution is an unprecedented level in the past 2000 or more, and the estimated temperature at the time when the earth was the warmest in the past 100,000 years. It is mentioned that it exceeds the above, and that it is almost in agreement with the estimated temperature value calculated by considering both human activity and the influence of nature.
One of the authors "Achieving conventional goals"
One of the authors of the report, Seita Emori, Deputy Director of the Earth System Area of the National Institute for Environmental Studies, said, "Although the direction has not changed significantly from the previous reports, the cause of global warming is human activity. Various issues such as what I said were elaborate and clear. It was newly analyzed that the global average temperature rise could reach 1.5 degrees by 2040, but the target set by the Paris Agreement was firmly set. I think that it has been confirmed again that it must be realized. "
The goal of Japan's global warming countermeasures is
Japan, which has the fifth highest greenhouse gas emissions in the world, has announced new goals for emission reductions since last year as measures are being taken by Western countries.
In October last year, we set the goal of achieving "carbon neutral", which will reduce domestic greenhouse gas emissions to zero as a whole by 2050.
In April, it also announced a goal to reduce greenhouse gas emissions in 2030 by 46% compared to 2013.
Furthermore, in order to achieve this goal last month, the ratio of renewable energy in the power source composition in 2030 was doubled from the current level to "36% to 38%", and the thermal power that emits carbon dioxide is 75. It also announced a policy to significantly reduce it from% to 41%.
However, in Japan, which is mountainous and has a lot of forests, there are many challenges in achieving the goal, such as the lack of land suitable for renewable energy power generation and the voices of opposition to construction in various places.
The international community will also focus on dealing with the export of coal-fired power generation.
Until now, Japan has taken a policy of supporting the export of coal-fired power generation only for those with high power generation efficiency, but at the G7 Summit = Summit of the Seven Major Countries in June, emission reduction measures were taken. It was agreed that the government would end export support by the end of the year for coal-fired power generation that has not been released.
For this reason, Japan is required to reconsider the conditions under which export support can be continued.
Japan's climate Future forecast
How will the weather in Japan change due to global warming?
The Japan Meteorological Agency and the Ministry of Education, Culture, Sports, Science and Technology have made forecasts for the end of this century and announced them in December last year.
With two assumptions, the goal of the "Paris Agreement" was achieved, and the temperature rise of the entire world was suppressed to around 2 degrees Celsius at the end of this century compared to before the Industrial Revolution, and no additional measures were taken.4 It is when it rises around the degree.
The worst hot days are more than half a month
First is the heat.
It is said that on a hot day of 35 degrees or higher, the national average will increase by about 2.8 days even if the temperature rise in the world is suppressed to around 2 degrees.
In addition, assuming that the temperature has risen by about 4 degrees, it is predicted that the average number of hot days will increase by about 19.1 days, which is more than half a month.
In the 30 years up to last year, the average number of days at 13 locations nationwide is about 2.5 days.
Very heavy rain frequency doubled
The amount of rain is expected to increase further.
Comparing the end of the 20th century and the end of this century, the frequency of "extremely heavy rain" of 50 mm or more per hour is expected to increase by about 1.6 times on a national average, and is expected to increase by about 4 degrees. Then, it will increase up to about 2.3 times.
It is said that the number of days with heavy rainfall of 200 mm or more per day will increase by about 1.5 times when it is assumed to rise by about 2 degrees, and by about 2.3 times when it is expected to rise by about 4 degrees.
The frequency of violent typhoons is increasing
In addition, as for typhoons, the amount of water vapor in the atmosphere increases, so it is said that the frequency of violent typhoons will increase under the assumption that the temperature will rise by around 4 degrees.
The average sea level on the coast of Japan is predicted to rise by about 0.39 meters when it rises by about 2 degrees, and by about 0.71 meters when it rises by 4 degrees, which may increase the risk of inundation damage due to storm surges and high waves.
The possibility of a powerful typhoon landing is increasing
Typhoon experts point out that these rising sea surface temperatures increase the risk of typhoons landing with strong force.
Research groups such as Professor Masaki Sato of the Atmosphere and Ocean Research Institute of the University of Tokyo have slightly changed the position and strength of typhoon occurrence and atmospheric conditions for typhoon No. 10 last year, and the course and strength of the typhoon can be changed. We simulated 50 patterns of how it would change.
Last year's Typhoon No. 10 temporarily became a fierce force with a central pressure of 910 hectopascals and a maximum wind speed of 55 meters, and experts pointed out that it was a "super typhoon class", and the Japan Meteorological Agency called for the highest level of caution. rice field.
However, it weakened just before approaching Kyushu, and did not land in the west of Kyushu.
When the virtual "Typhoon No. 10" was generated in this simulation, most of the routes went to Kyushu and Shikoku, and some of them landed at a strength lower than 930 hectopascals.
Professor Sato says that it is quite possible that a typhoon such as Typhoon No. 10 will land if the sea surface temperature becomes as high as last summer.
Professor Sato pointed out, "As global warming progresses, the possibility of a powerful typhoon landing will increase. It is important to stay alert and prepare for it just because it was okay last year." I am.
Around Japan “Frequent occurrence after 10 years of the highest sea surface temperature in history” Expert analysis
"The" highest sea surface temperature in the history of observation "will occur once every two years in 10 years at the earliest."
This is the forecast result of sea surface temperature around Japan based on the scenario used in this IPCC report.
Experts warn that "even if the goals of the Paris Agreement are achieved, the risk of typhoons and heavy rains will increase."
Research groups such as Research Fellow Michiya Hayashi of the National Institute for Environmental Studies will analyze in detail how the sea surface temperature around Japan will change in the near future based on the greenhouse gas emission scenarios used by the IPCC in this report. Did.
Over the last 30 years, the average sea surface temperature around Japan has continued to rise, reaching around 30 degrees Celsius over a wide area in August last year, the highest since we started collecting statistics.
When the research team analyzed the simulation results of future sea surface temperature, the sea surface temperature that exceeds August last year will be more than once every two years from 2031 to 2050, which is 10 to 30 years from now. It turns out that it happens more often.
It is said that such water temperature would have occurred less than once every 1000 years if greenhouse gases did not increase due to human activities after the Industrial Revolution.
On the screen that predicts the average sea surface temperature in August, you can see that the sea surface temperature around Japan will reach 29 degrees or 30 degrees over a wide range.
According to Fellow Hayashi, such a rise in sea surface temperature may be unavoidable even if the goal of the Paris Agreement is to limit the rise in global average temperature to 1.5 degrees Celsius from before the Industrial Revolution. It's expensive.
"When the sea surface temperature rises, there is an increased risk that the typhoon will approach or land in Japan without losing its power, and it may affect the fishing industry," said Hayashi.
IPCC Chair Calls on Countries to Accelerate Measures
IPCC Chairman Lee Hye-sung said at a press conference in conjunction with the release of the report, "It is indisputable that human activity is causing climate change and making extreme weather events more frequent and serious. The report also shows that climate change is affecting every part of the globe. To curb global warming, reduce greenhouse gas emissions quickly and significantly. It is clear that there is a need, "he said, calling on countries to accelerate their efforts.
Minister of the Environment Koizumi talks "We will do our best to strengthen bold policies"
Regarding the IPCC report, Minister of the Environment Koizumi said, "Based on the important scientific findings reported this time, Japan's environmental diplomacy will raise ambition with the countries of the world and lead to the steady implementation of the Paris Agreement. We will exert our strength. "
On top of that, he said, "In response to the climate crisis that has already had an impact, in order to curb the temperature rise to 1.5 ° C, we must first do our utmost to boldly strengthen policies, including carbon pricing, toward 2030. Was renewed. "