Cambio climático: Universidad ...
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As for the
future,
it is not a
Cambio climático:
question of
foreseing it
causas y consecuencias.
” Pour ce qui est de l’avenir, il ne s’agit pas de le prévoir,
mais de le rendre possible. “
– Antoine de Saint Exupéry, Citadelle, 1948
J. Fidel González Rouco Facultad CC. Químicas 20.10.2021
fidelgr@fis.ucm.es
Departamento de Física de la Tierra y Astrofísica
IGEO-UCM
Universidad Complutense de Madrid
UCM
As for the
future,
it is not a
Cambio climático:
question of
foreseing it
causas y consecuencias.
” Pour ce qui est de l’avenir, il ne s’agit pas de le prévoir,
mais de le rendre possible. “
– Antoine de Saint Exupéry, Citadelle, 1948
1. ¿Cómo sabemos que el cambio climático actual está producido por las
actividades humanas?
2. ¿Cómo estimamos el cambio climático futuro?
3. ¿Estamos en una situación de emergencia?
4. ¿Qué posibilidades tenemos para controlar el cambio climático en el futuro?
5. ¿Es importante para los ODS?
Observed changes in the climate system: atmosphere & ocean
-Hartmann et al., IPCC, 2013: Ch2-
Updated
Earth has been in radiative imbalance with more engergy entering than leaving
the system since ~ 1970s.
It is virtually certain that temperatures have increased more than 1K since the
late 19th century. 3
Observed changes in the climate system: atmosphere & ocean
Warming is unequivocal, both in the atmosphere and ocean… but not only
4
Earth’s temperature is the result of radiative balance
~342Wm-2
30%
49%
T= -18ºc 15 ºC
5
N
Radiative forcing factors
O
I
Natural and anthropogenic energy drivers
T
I
AL S
I
ED
N R
Natural forcings: volcanic, solar, orbital
FI VE
Anthropogenic forcings: greenhouse gases,
aerosols, land use land cover changes
TO D
T TE
TO D
T TE
P
EC E
P
BJ C
EC E
AC
BJ C
(IPCC 2021, Fig TS9)
AC
U
6
What causes present climate change?
We need to use tools that allow for evaluating the efects of external forcing
changes: los modelos climáticos
• Climate models are computer codes
that resolve the equations of the
dynamics of the various climate
system components (atmosphere,
ocean, cryosphere, biosphere…) and
their interactions.
• The ‘dynamics’ solves the Navier
Stokes equations in an spatial grid.
The ‘physics’ consists on
parameterizing the sub-grid scale
proceses that are not explicitely solved
in the grid resolution.
Syukuro Manabe. Nobel Fisica 2021
7
What causes system changes?: model evaluation & detection/attribution
Human influence on the climate system is clear
...from increasing GHGs, radiative forcing,
warming and understanding of changes
(IPCC 2013, Fig. TS.9)
Climate models improve continuously
CMIP5+6 models reproduce observed
continental-scale surface T patterns and trends
over many decades including the more rapid
warming since the mid-20th century and post
volcanic cooling (very high conf.)
Natural forcings only
-Flato et al., IPCC, 2013: Ch9-
- Bindoff et al., IPCC, 2013: Ch10-
Klaus Hasselmann.
Nobel Fisica 2021
Natural & Anthr.
forcing
8
Future climate change
Scenario projections
-Ciais et al., IPCC, 2013: Ch6-
- Collins et al., IPCC, 2013: Ch12-
Representative Concentration Pathways are used as boundary conditions for
climate change simulations.
9
Future
uture climate change
emissions cause future additional warming with total warming
dominated by past and future CO emissions
Scenario projections -IPCC, 2021-
a) uture annual emissions of C (le ) and of a subset of ey non-C drivers (right) across ve illustrative scenarios
Carbon dioxide (GtCO₂/yr) elected contributors to non-C GHGs
Methane (MtCH /yr)
140
800 SSP3-7.0
SSP5-8.5 600
SSP5-8.5
120 400
SSP2-4.5
200
SSP1-2.6
100 0 SSP1-1.9
2015 2050 2100
SSP3-7.0
80 Nitrous oxide (MtN₂O/yr)
SSP3-7.0
20
60 SSP5-8.5
10 SSP2-4.5
SSP1-2.6
SSP1-1.9
40 0
2015 2050 2100
20 ne air pollutant and contributor to aerosols
SSP2-4.5 Sulfur dioxide (MtSO₂/yr)
0 120
SSP1-2.6
80 SSP3-7.0
SSP1-1.9
-20
40 SSP2-4.5
2015 2050 2100 SSP5-8.5
SSP1-1.9
0 SSP1-2.6
2015 2050 2100
b) Contribution to global surface temperature increase from di erent emissions with a dominant role of C 10
emissionsFuture climate change
Scenario projections
Temperature increase by the end of the 21st century will likely
exceed 1.5 ºC relative to preindustrial for all RCPs
... likely ∆T> 2ºC for RCP6.0 and RCP8.5
... more likely than not ∆T> 2ºC for RCP4.5
11Future climate change
Scenario projections
Continued emissions of
GHGs will cause further
warming and changes in
all components of the
climate system.
Limiting climate change
will requiere substantial
and sustained reduction
of GHGs.
(IPCC 2013, SPM.7 TS.15)
12Policy relevant implications: commitment, stabilization & irreversibility
Climate change commitment: future change to which the climate system is committed by virtue of
past and current forcings. It brings the concept of inertia
C o n s t a n t
composition
c o m m i t m e n t
represents future
warming associated
with current CO2
concentrations
Zero emissions
commitment:
Warming from past
CO2 emissions.
-Matthews & Weaver: Nature CC, 3, 143, 2010- 13Policy relevant implications: commitment, stabilization & irreversibility
14Policy relevant implications: commitment, stabilization & irreversibility
15Policy relevant implications: commitment, stabilization & irreversibility
Cumulative emissions of
CO2 largely determine
global mean surface
warming by the late 21st
(IPCC 2013, SPM.10)
century and beyond.
Limiting climate change
will requiere substantial
and substained emission
reductions.
This represents a
substantial multi century
climate change
commitment created by
past, present and future
emissions..
- Collins et al., IPCC, 2013: Ch12-
16Policy relevant implications: commitment, stabilization & irreversibility
-IPCC, 2021-
17Summary for Policymakers
Policy relevant implications: commitment, stabilization & irreversibility
Cumulative emissions of CO2 and future non-CO2 radiative forcing determine
Cummulative
the emisions
probability of CO2
of limiting and other
warming GHGs determine the possibility of
to 1.5°C
reducing global temperature increase to 1.5 ºC
a) Observed global temperature change and modeled
responses to stylized anthropogenic emission and forcing pathways
Global warming relative to 1850-1900 (°C)
2.0
1.5
Observed monthly global
(IPCC SR15 2018, SPM 1)
mean surface temperature
Estimated anthropogenic
1.0
warming to date and
likely range
Likely range of modeled responses to stylized pathways
Global CO2 emissions reach net zero in 2055 while net
non-CO2 radiative forcing is reduced after 2030 (grey in b, c & d)
0.5
2017 Faster CO2 reductions (blue in b & c) result in a higher
probability of limiting warming to 1.5°C
No reduction of net non-CO2 radiative forcing (purple in d)
results in a lower probability of limiting warming to 1.5°C
0
1960 1980 2000 2020 2040 2060 2080 2100
-b)
Rogelj et al., 2018. SR1.5-
Stylized net global CO2 emission pathways
Billion tonnes CO2 per year (GtCO2/yr)
c) Cumulative net CO2 emissions
Billion tonnes CO2 (GtCO2)
d) Non-CO2 radiative forcing pathways
Watts per square metre (W/m2)
18Policy relevant implications: commitment, stabilization & irreversibility
Global emissions pathway characteristics
General characteristics of the evolution of anthropogenic net emissions of CO2, and total emissions of
methane, black carbon, and nitrous oxide in model pathways that limit global warming to 1.5°C with no or
Cummulative emisions
limited overshoot. of CO2
Net emissions and other
are defined GHGs determine
as anthropogenic the by
emissions reduced possibility
anthropogenicof
reducing global temperature increase to 1.5 ºC
removals. Reductions in net emissions can be achieved through different portfolios of mitigation measures
illustrated in Figure SPM.3b.
Non-CO2 emissions relative to 2010
Global total net CO2 emissions Emissions of non-CO2 forcers are also reduced
or limited in pathways limiting global warming
Billion tonnes of CO2/yr to 1.5°C with no or limited overshoot, but
50 they do not reach zero globally.
Methane emissions
40 In pathways limiting global warming to 1.5°C 1
with no or limited overshoot as well as in
pathways with a higher overshoot, CO2 emissions
30 are reduced to net zero globally around 2050.
0
2020 2040 2060 2080 2100
20
Black carbon emissions
(IPCC SR15 2018, SPM 1)
1
10
Four illustrative model pathways
0 0
2020 2040 2060 2080 2100
P1
P2
Nitrous oxide emissions
-10
P3
1
-20
P4
0
2010 2020 2030 2040 2050 2060 2070 2080 2090 2100 2020 2040 2060 2080 2100
Timing of net zero CO2 Pathways limiting global warming to 1.5°C with no or limited overshoot
Line widths depict the 5-95th Pathways with higher overshoot
percentile and the 25-75th Pathways limiting global warming below 2°C
percentile of scenarios (Not shown above)
- Rogelj et al., 2018. SR1.5- 19
Figure SPM.3a | Global emissions pathway characteristics. The main panel shows global net anthropogenic CO2 emissions in pathways limiting global warming1.5 ºC vs. 2ºC, what difference does it make?
Differences between
scenarios are highly non
linear. Implications of a
+ 0.5 ºC are severe…
.... and ugly surprises
are more likely above
1.5 ºC
- Rogelj et al., 2018. SR1.5- 20As for the future, it is not a question of foreseing it, but of making it possible
Antoine de Saint Exupéry, Citadelle, 1948
a) El cambio climático actual lo producen las actividades humanas.
b) Podemos estimar la magnitud del cambio futuro y sus incertidumbres. La
mayor contribución a las incertidumbres son las emisiones futuras.
c) Es posible limitar el calentamiento global. Para ello se necesitan
transformaciones sin precedentes en la tecnología, modelo energético…
d) Las estrategias de adaptación y mitigación son necesarias para desarrollar
los ODS 2030. Framing and Context Chapte
e) El papel de las universidades: educación, investigación, debate educado/
Cross-Chapter Box 4 (continued)
informado/resposable…
à estimación de emisiones
à grupos de colaboración
à justicia climática
Grupos
de
Sostenibi
lidad - Allen et al., 2018. SR1.5-
Cross-Chapter Box 4, Figure 1 | Climate action is number 13 of the UN Sustainable Development Goals.
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