Climate is the long-term pattern of weather in an area, typically averaged over a period of 30 years. More rigorously, it is the mean and variability of meteorological variables over a time spanning from months to millions of years. Some of the meteorological variables that are commonly measured are temperature, humidity, atmospheric pressure, wind and precipitation. In a broader sense, climate is the state of the components of the climate system, which includes the ocean, land, and ice on Earth. The climate of a location is affected by its latitude/longitude, terrain, and altitude, as well as nearby water bodies and their currents.
Climates can be classified according to the average and the typical ranges of different variables, most commonly temperature and precipitation. The most commonly used classification scheme was the Köppen climate classification. The Thornthwaite system, in use since 1948, incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it.
Climate models are mathematical models of past, present and future climates. Climate change may occur over long and short timescales from a variety of factors; recent warming is discussed in global warming. Global warming results in redistributions.
Scientists representing each of the IPCC's member states analysed more than 14,000 papers. The report traces a harsh reality.
The international Paris Agreement to combat climate change went into effect last year and aims to keep the average rise in temperatures in this century down to 1.5 degrees Celsius higher than pre-industrial levels. But the report states we have already presided over a rise of 1.1 C, and within the next 20 years we will have exceeded the 1.5 C mark.
The chances of abnormal heat waves, torrential rains and droughts being witnessed across the world are being made greater by global warming. The effect on East Asia, including Japan, is marked. Torrential rains and intense heat spells are expected to be more frequent in the future.
This year has seen major flooding in China and Germany, among other countries. North America has been hit by heatwaves. Japan, too, is now subject to torrential rain disasters on an almost annual basis. The climate crisis threatens peoples' way of life and their lives themselves.
The report also shows how we can avoid the worst scenario. If the whole world can bring its greenhouse gas emissions down to virtually zero, there is a chance we could reach the 1.5 C target by the end of this century. We are under pressure to accelerate and strengthen our countermeasures.
The IPCC report has become the basis for international diplomacy and policy formulation. This autumn, the U.K. will host the 26th U.N. Climate Change Conference (COP26).
Japan has pledged to reduce its greenhouse gas emissions to 46 per cent of fiscal 2013 levels by fiscal 2030, and to effectively zero by fiscal 2050. The U.S. and Europe have put forward more ambitious targets.
Achieving this requires engagement from China, the country with the highest emissions on Earth, and developing nations slow to decarbonise.
United Nations Secretary-General Antonio Guterres has described the latest report as a "code red for humanity." What is in question now is whether the countries participating in COP26 can present a united front to put forward significant emissions reduction targets.
In past negotiations on climate change measures, developed and developing nations have repeatedly been at odds. Each country must take this report as an opportunity to deepen international cooperation.