31
From the Climates of the Past
to the Climates of the Future
Sylvie Charbit, Nathaelle Bouttes, Aurélien Quiquet, Laurent Bopp,
Gilles Ramstein, Jean-Louis Dufresne, and Julien Cattiaux
This chapter connects everything we have learned about past
climates (both from the analysis of natural archives and from
numerical simulations), and future climate projections. The
models used to explore the future are similar to those used for
past climates, except that the results are based on emission
scenarios of greenhouse gas emissions whereas past climate
simulations may be compared to reconstructions from the
natural archives described in volume 1. The climate of the
past 1000 years can be seen as the ‘background noise’ of the
recent natural evolution of the climate system. On this basis,
the current climate change can be analyzed. Over the longer
term, analysis of ice cores allows us to trace back the history
of atmospheric CO 2 concentration over the last
800,000 years, and shows that the anthropogenic disturbance
(producing an atmospheric CO 2 concentration currently in
excess of 410 ppm) is completely outside the documented
glacial-interglacial variations over the last million years,
ranging from 180 to 280 ppm. With this awareness you are
well equipped to now explore the climate of the future.
Climate Observations in Recent Decades: The
First Signs of Warming
The principles of the physical laws governing the temperature on the Earth’s surface were formulated at the beginning
of the nineteenth century by Joseph Fourier, who established
that the energy balance at the surface of our planet is
dominated by incoming solar radiation which is the primary
source of energy, and infrared emission exchanges which
control energy losses. He concluded that any change in
surface conditions could lead to a change in climate and
argued that the development and progress of human societies
can notably change the state of the ground surface over vast
regions, as well as the distribution of waters and the great
movements of the air and that such effects have the ability to
cause the mean degree of heat to vary over the course of
several centuries. Joseph Fourier also identified the trapping
of infrared radiation by the gases in the atmosphere (Fourier
1824).
This was the beginning of the greenhouse effect theory.
Starting from this seminal work, numerous studies were
conducted throughout the nineteenth and twentieth centuries. Within a scientific context where the understanding of
the glacial-interglacial cycles was the matter of a very hot
debate, the Swedish chemist Svante Arrhenius was the first
one to quantify the effect of the atmospheric carbon dioxide
concentration on the average surface temperature of the
Earth and to suggest that substantial variations of the
atmospheric CO 2 levels could explain the glacial advances
and retreats. However, it is only since the late 1970s that we
can calculate precisely the radiation exchanges using radiative transfer codes and spectral databases to break down
energy by wavelength.
Long time refuted, or at least underestimated, global
warming has now become an incontrovertible reality: in
2001, the scientific review by the Intergovernmental Panel
on Climate Change (IPCC) concluded that there was a
growing body of evidence confirming global warming as
well as other changes in the climate system. Based on the
results of numerical experiments with coupled
atmosphere-ocean general circulation models (AOGCMs),
the Fifth IPCC Assessment Report, published in September
2013 (IPCC 2013), established with a probability of more
than 95%, that the global warming observed in recent decades is due to anthropogenic activities. This situation has no
S. Charbit (&) Á N. Bouttes Á A. Quiquet Á L. Bopp Á G. Ramstein
Laboratoire des Sciences du Climat et de l’Environnement,
LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91190
Gif-sur-Yvette, France
e-mail: Sylvie.Charbit@lsce.ipsl.fr
J.-L. Dufresne
Laboratoire de Météorologie Dynamique/IPSL, Université Pierre
et Marie Curie, BP 99, 4 Place Jussieu, Cedex 05, 75252 Paris,
France
J. Cattiaux
Centre National de Recherches Météorologiques, Université de
Toulouse, CNRS, Météo-France, 42 Avenue Gaspard Coriolis,
31057 Toulouse Cedex, France
© Springer Nature Switzerland AG 2021
G. Ramstein et al. (eds.), Paleoclimatology, Frontiers in Earth Sciences,
https://doi.org/10.1007/978-3-030-24982-3_31
443
From the Climates of the Past
to the Climates of the Future
Sylvie Charbit, Nathaelle Bouttes, Aurélien Quiquet, Laurent Bopp,
Gilles Ramstein, Jean-Louis Dufresne, and Julien Cattiaux
This chapter connects everything we have learned about past
climates (both from the analysis of natural archives and from
numerical simulations), and future climate projections. The
models used to explore the future are similar to those used for
past climates, except that the results are based on emission
scenarios of greenhouse gas emissions whereas past climate
simulations may be compared to reconstructions from the
natural archives described in volume 1. The climate of the
past 1000 years can be seen as the ‘background noise’ of the
recent natural evolution of the climate system. On this basis,
the current climate change can be analyzed. Over the longer
term, analysis of ice cores allows us to trace back the history
of atmospheric CO 2 concentration over the last
800,000 years, and shows that the anthropogenic disturbance
(producing an atmospheric CO 2 concentration currently in
excess of 410 ppm) is completely outside the documented
glacial-interglacial variations over the last million years,
ranging from 180 to 280 ppm. With this awareness you are
well equipped to now explore the climate of the future.
Climate Observations in Recent Decades: The
First Signs of Warming
The principles of the physical laws governing the temperature on the Earth’s surface were formulated at the beginning
of the nineteenth century by Joseph Fourier, who established
that the energy balance at the surface of our planet is
dominated by incoming solar radiation which is the primary
source of energy, and infrared emission exchanges which
control energy losses. He concluded that any change in
surface conditions could lead to a change in climate and
argued that the development and progress of human societies
can notably change the state of the ground surface over vast
regions, as well as the distribution of waters and the great
movements of the air and that such effects have the ability to
cause the mean degree of heat to vary over the course of
several centuries. Joseph Fourier also identified the trapping
of infrared radiation by the gases in the atmosphere (Fourier
1824).
This was the beginning of the greenhouse effect theory.
Starting from this seminal work, numerous studies were
conducted throughout the nineteenth and twentieth centuries. Within a scientific context where the understanding of
the glacial-interglacial cycles was the matter of a very hot
debate, the Swedish chemist Svante Arrhenius was the first
one to quantify the effect of the atmospheric carbon dioxide
concentration on the average surface temperature of the
Earth and to suggest that substantial variations of the
atmospheric CO 2 levels could explain the glacial advances
and retreats. However, it is only since the late 1970s that we
can calculate precisely the radiation exchanges using radiative transfer codes and spectral databases to break down
energy by wavelength.
Long time refuted, or at least underestimated, global
warming has now become an incontrovertible reality: in
2001, the scientific review by the Intergovernmental Panel
on Climate Change (IPCC) concluded that there was a
growing body of evidence confirming global warming as
well as other changes in the climate system. Based on the
results of numerical experiments with coupled
atmosphere-ocean general circulation models (AOGCMs),
the Fifth IPCC Assessment Report, published in September
2013 (IPCC 2013), established with a probability of more
than 95%, that the global warming observed in recent decades is due to anthropogenic activities. This situation has no
S. Charbit (&) Á N. Bouttes Á A. Quiquet Á L. Bopp Á G. Ramstein
Laboratoire des Sciences du Climat et de l’Environnement,
LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91190
Gif-sur-Yvette, France
e-mail: Sylvie.Charbit@lsce.ipsl.fr
J.-L. Dufresne
Laboratoire de Météorologie Dynamique/IPSL, Université Pierre
et Marie Curie, BP 99, 4 Place Jussieu, Cedex 05, 75252 Paris,
France
J. Cattiaux
Centre National de Recherches Météorologiques, Université de
Toulouse, CNRS, Météo-France, 42 Avenue Gaspard Coriolis,
31057 Toulouse Cedex, France
© Springer Nature Switzerland AG 2021
G. Ramstein et al. (eds.), Paleoclimatology, Frontiers in Earth Sciences,
https://doi.org/10.1007/978-3-030-24982-3_31
443