daily data in the period 1861–2005 and from 2016 thereafter with projections until
2100 under profiles RCP8.5 and RCP4.5 of the AR5 Report. The modeling strategy
considered distinct climate sensitivities, physical parameterization, and resolutions,
through CMIP5, and the influence of internal variability, through CESM.
Four heatwave variables which were the sum of heatwave days, the total number
of discrete events, length of the longest event, and peak wave intensity, were
evaluated during a 5-month summer season. Results were obtained at the global
level and for 21 land-based regions, for both global mean warming and heatwave
thresholds relative to pre-industrial conditions. These results were assumed as
applicable to heatwave and mitigation strategies.
The higher changes in heatwave days occurred in the tropics with 30 additional
days per season and per °C of global temperature rise. These latter events occur
over vast areas of Africa, Central and South America, and Southeast Asia. In mid to
high latitudes, the variation was less drastic with 10–15 extra days expected over
Northern Europe, North America, and Russia. Over South Australia and higher
latitudes of South America, the correspondent value of extra days ranged from 4 to
8 per degree of global warming.
Also, over most regions, the number of heatwaves per season was expected to
rise by about 1.5–2 events per degree of global warming, excepting Central and
Southern Africa and Central Asia where an increase of 2.5 events per season was
forecasted. The median change in the longest heatwave duration period ranged from
1 to 3 days with smaller ranges in higher latitudes, and estimated ranges of 4–
6 days per degree of global warming over India, Southeast Asia, the US, and South
America.
In Central America, African areas, and the Middle East, the longest heatwave
period was projected to increase by 10–12 days per degree of global warming.
About the peak wave intensity, it was concluded that the temperature of the hottest
heatwave day per season was expected to rise between 1.2 and 1.5 °C per degree of
global warming, by 1.8 °C across the US, south of Southern America, and some of
the African areas, by 2 °C in Europe, and by 1.1 °C in Australia and Southeast Asia.
There is a huge variation of heat warming events and mean warming at regional
levels, comparatively with global temperature increase. Over high latitudes in
Alaska, Greenland, and North Asia, regional mean warming is twofold higher than
global warming. In lower latitudes in the south of southern South America, south
and Southeast Asia, and Australia, the regional mean warming is about the same
order of magnitude as the global average. Variation in regional and seasonal
changes in heatwave days is linear with a widespread. The increase in heatwave
days with the global average temperature is much faster in tropical regions than in
higher latitudes. Regions with larger overall maximum increases of around
150 days of heatwave days are those with average temperature change rates
increasing between 2.5 and 3 °C.
The study of Perkins-Kirkpatrick and Gibson (2017) mentioned above, described
the sensitivity of heatwave frequency in relation to the average global warming.
Different thresholds of global warming imply different patterns in terms of regional
changes in heatwave days. For example, with a global warming of 5 °C until 2100,
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8 Fundamentals of Global Carbon Budgets and Climate Change
2100 under profiles RCP8.5 and RCP4.5 of the AR5 Report. The modeling strategy
considered distinct climate sensitivities, physical parameterization, and resolutions,
through CMIP5, and the influence of internal variability, through CESM.
Four heatwave variables which were the sum of heatwave days, the total number
of discrete events, length of the longest event, and peak wave intensity, were
evaluated during a 5-month summer season. Results were obtained at the global
level and for 21 land-based regions, for both global mean warming and heatwave
thresholds relative to pre-industrial conditions. These results were assumed as
applicable to heatwave and mitigation strategies.
The higher changes in heatwave days occurred in the tropics with 30 additional
days per season and per °C of global temperature rise. These latter events occur
over vast areas of Africa, Central and South America, and Southeast Asia. In mid to
high latitudes, the variation was less drastic with 10–15 extra days expected over
Northern Europe, North America, and Russia. Over South Australia and higher
latitudes of South America, the correspondent value of extra days ranged from 4 to
8 per degree of global warming.
Also, over most regions, the number of heatwaves per season was expected to
rise by about 1.5–2 events per degree of global warming, excepting Central and
Southern Africa and Central Asia where an increase of 2.5 events per season was
forecasted. The median change in the longest heatwave duration period ranged from
1 to 3 days with smaller ranges in higher latitudes, and estimated ranges of 4–
6 days per degree of global warming over India, Southeast Asia, the US, and South
America.
In Central America, African areas, and the Middle East, the longest heatwave
period was projected to increase by 10–12 days per degree of global warming.
About the peak wave intensity, it was concluded that the temperature of the hottest
heatwave day per season was expected to rise between 1.2 and 1.5 °C per degree of
global warming, by 1.8 °C across the US, south of Southern America, and some of
the African areas, by 2 °C in Europe, and by 1.1 °C in Australia and Southeast Asia.
There is a huge variation of heat warming events and mean warming at regional
levels, comparatively with global temperature increase. Over high latitudes in
Alaska, Greenland, and North Asia, regional mean warming is twofold higher than
global warming. In lower latitudes in the south of southern South America, south
and Southeast Asia, and Australia, the regional mean warming is about the same
order of magnitude as the global average. Variation in regional and seasonal
changes in heatwave days is linear with a widespread. The increase in heatwave
days with the global average temperature is much faster in tropical regions than in
higher latitudes. Regions with larger overall maximum increases of around
150 days of heatwave days are those with average temperature change rates
increasing between 2.5 and 3 °C.
The study of Perkins-Kirkpatrick and Gibson (2017) mentioned above, described
the sensitivity of heatwave frequency in relation to the average global warming.
Different thresholds of global warming imply different patterns in terms of regional
changes in heatwave days. For example, with a global warming of 5 °C until 2100,
284
8 Fundamentals of Global Carbon Budgets and Climate Change