Nick Brooks

1
An Introduction to the Science of Climate Change
Nick Brooks Visiting Research Fellow Tyndall
Centre for Climate Change Research School of
Environmental Sciences University of East
Anglia Norwich NR4 7TJ. Email
nick.brooks_at_uea.ac.uk. http//www.cru.uea.ac.uk/e
118/welcome.htm
2
Structure of this presentation

• The long-term context past climate change

• Climate change today the scientific background

• Climate change scenarios projections and targets

• Manifestations of climate change extremes,
  long-term abrupt changes

• Conclusions very general implications for
  development

• Discussion

3
Past Climate Change
A very brief overview (the past few 100,000 years)
4
Climate has always changed

• Over past 3 million yrs climate dominated by
  glacial-interglacial cycles

• Modern humans emerged by 200,000 yrs ago
• Global mean surface temperature
• Last interglacial 125,000 yrs ago 1-2º C warmer
  than present
• Last Glacial Maximum 21,000 yrs ago 4-7º C
  cooler than present

Over long timescales1, climate change has been
driven predominantly by cyclical changes in the
Earths orbit which control the seasonal and
latitudinal distribution of solar heating across
the Earths surface, at least for the past 3
million years. 1thousands to tens of thousands of
years,
Ref IPCC AR4 WGI Ch. 6 (Jansen et al. , 2007)
5
Sea-level indicator of climate change

• Last Interglacial
• 4-6m above present
• 125,000 yrs ago

• Last Glacial Maximum
• 120 m below present
• 21,000 yrs ago

Left Sea-levels over the past 32,000 and (inset)
120,000 years relative to current levels,
reconstructed from records at different locations
(from Jansen et al., 2007, p. 458)
Ref IPCC AR4 WGI Ch. 6 (Jansen et al. , 2007)
6
Last Glacial Maximum
Glacial cycles and aridity

• Last Glacial Maximum (21,000 yrs ago)
• widespread aridity, expanded deserts

• Last Glacial Maximum (10-5000 yrs ago)
• warm, humid, deserts reduced or absent

Palaeovegetation maps by J. Adams (Oak Ridge Nat.
Lab., USA) http//www.esd.ornl.gov/projects/qen/ne
rcAFRICA.html
7
The last great global climatic reorganisation

• Between 5800 5200 years ago
• Response to cyclical changes in Earths orbit -
  tipping point
• Cooler conditions in middle and high latitudes
• Desiccation of northern hemisphere sub-tropics
  (e.g. Afro-Asiatic desert belt)
• Regular El Niño established
• Global cooling of lt 0.4 C

Abrupt collapse of Saharan vegetation indicated
by large increase in dust deposition in E.
tropical Atlantic (below)
Main image lake sediments in the Libyan
Sahara Graphic de Menocal et al. (2000)
Reference Brooks (2006)
8
Human impacts of last global climatic upheaval
Climate Change Civilisation

• Profound impacts on human societies across globe
• Collapse of ecosystems resources in many areas
• Widespread migration, numerous cultural
  transitions
• Earliest civilisations arise in areas facing
  extreme climatic deterioration, in locations with
  last remaining resources

Left Human occupation in the Sahara-Sahel zone
north of 23 N (blue) and south of 23 N (clear),
showing increase of population in wetter regions
in south and collapse in occupation in north
5000 yrs ago as monsoon fails. Right The Nile
Valley - a refuge for those fleeing aridity in
the eastern Sahara
10 9 8 7 6 5
4 3 2
Time (1000s of yrs before present)
References Brooks (2006)
9
Present-Day Climate Change
Scientific background and observed/historical
changes
10
The enhanced greenhouse effect
Past changes experienced by human beings driven
by cyclical variations in Earths orbit, changes
in distribution of surface heating, natural
variability
Climate change today dominated by anthropogenic
factors, principally emissions of greenhouse gases
Source IPCC WGI Ch.1 (Somerville et al., 2007a,
p. 115)
11
Greenhouse gas concentrations are rising

• Increase since 1750 due to industrial activity
• Rapid rise over past 50 years
• Atmospheric CO2 concentration has remained below
  300 ppm for at least past 600,000 years
• Now at 379 ppm and rising (2005 values)

Source IPCC AR4 WGI Ch.6, p.444 (Jansen et al.,
2007)
12
Temperatures are rising
Source IPCC WGI Ch.3 (Trenberth et al.,2007, p.
253)
13
Attributing climate change to human activity
Source IPCC AR4 WGI Ch. 9 (Hegerl et al., 2007,
p. 684)
14
Global temperatures over the past 1,200 years
Source Science, 10 February 2005
Source Science Magazine (Kerr, 2005)
15
Observed changes

• Global mean temp. up by 0.74C over period
  1906-2005
• Frequency of warm extremes has increased, cold
  days down
• Arctic temperatures increased at twice global
  average rate
• Precipitation generally increased over land north
  of 30 N but down in tropics
• Substantial increases in heavy precipitation
  events
• Droughts have become more common
• Changes in large-scale atmospheric circulation
  apparent
• Tropical cyclones have become more destructive
• From IPCC AR4 WGI Ch.3 (Trenberth et a., 2007)

Palmer Drought Severity Index, from IPCC AR4 WGI
Ch.3, p.263 (Trenberth et al., 2007). -ve
indicates drier, wetter.
16
Climate Change Scenarios
Global projections, targets and dangerous
climate change
17
Climate change scenarios

• Storylines of social, economic, population,
  technological trends with associated emissions
  trajectories
• Set of scenarios used for IPCC projections - the
  six SRES1 marker scenarios
• low to high unmitigated emissions - no
  abatement policies

1Special Report on Emissions Scenarios,
(Nakicenovic et al., 2000)
Source IPCC 2007 - Summary for Policymakers, p.13
18
Projected warming trajectories to 2100
Multi-model global averages of surface warming
relative to 1980-1999 for different scenarios
(solid lines) 1 (shading). Grey bars indicate
best estimate (solid line within each bar)
likely range for the six SRES marker scenarios,
considering independent models and observational
constraints.
Source IPCC 2007 - Summary for Policymakers, p.14
19
Dangerous climate change and temperature
thresholds
Ultimate objective of United Nations Framework
Convention on Climate Change (UNFCCC) is
stabilisation of greenhouse gas concentrations
at a level that would prevent dangerous
anthropogenic interference with the climate
system. 1
Widely agreed guardrail value of 2º C - maximum
permissible rise in global mean surface
temperature, above late pre-industrial values, to
have reasonable chance of achieving this
objective (Anderson Bows, 2008)

• No human experience of more than 2º C above
  pre-industrial value
• Abrupt changes appear more likely for warming gt
  2º C

• Keeping below 2º C requires stabilisation of
  greenhouse gas concentrations below 450 parts per
  million of CO2 equivalent or less

• Threshold of 350 ppm for 93 probability of not
  exceeding 2º C (Anderson Bows, 2008)

1http//unfccc.int/essential_background/convention
/background/items/1353.php
20
The current situation

• CO2 concentration in 2005 was 379 ppm (IPCC, 2007)

• Current CO2 equivalent concentration estimated at
  455 ppm by IPCC (Rogner et al., 2007, p. 102)
  and at 412 ppm by Gohar Shine (2007)

• Considerable policy debate around a more
  realistic 550 ppm target (Anderson Bows, 2008)

• 550 ppm represents doubling of pre-industrial
  concentrations
• Likely to be associated with warming of 3 C
  (IPCC, 2007)

21
Future emissions and warming scenarios

• CO2 concentrations to double to 550 ppm
  mid-century for unmitigated scenarios
• Doubling likely to result in warming of 3º C
  (climate sensitivity)
• Must also factor in other greenhouse gases - CO2
  equivalent concentrations

Source IPCC AR4 WGI Ch. 10 (Meehl et al., 2007,
p. 803)
22
How are we doing?

• Greenhouse gas concentrations currently rising
  faster than projected by even the most
  pessimistic scenarios (e.g. Pittock, 2008)
• SRES scenarios need updating

23
What can we expect over the 21st century?

• Without radical action for large emissions
  starting by 2015
• 2º C threshold will be breached (possibly
  inevitable at current concentrations)
• Greenhouse gas concs. will almost certainly more
  than double before 2100
• Global temperatures likely to rise by gt 3º C
  before 2100 (4-6º C plausible)

• A world warmed by 3º C
• Currently seems likely by 2070s
• Comparable global mean surface temperature last
  seen 3.5 million yrs ago
• Sea-levels 15-20 m above modern levels1
• Suggestions of permanent El Niño-like
  conditions2,3
• Associated with elevated risks of abrupt
  changes in climate, landscapes, etc4

• Warming of gt 3º C
• No past analogues (similar temps. millions of yrs
  ago different continental configurations and
  constraints on climatic behaviour)

1Jansen et al., 2007 2Haywood et al., 2009
3Wunsch, 2009 4Warren, 2006
24
How Will Climate Change Manifest Itself?
Climate extremes, long-term change and tipping
points in the Earth system
25
IPCC temp. projections 3 different scenarios, 3
time-slices
Source IPCC AR4 WGI Ch.10 (Meehl et al., 2007,
p.766)
26
Warming heat extremes an illustrative example
2003 European heat wave
Distribution of summer (average) temperatures in
Switzerland from 1864-2003
Heat wave was associated with widespread
mortality, especially elderly Average temperature
during 2003 heat wave was 22C, far outside
recorded range (mean value 17C). Very unlikely
in the context of historical climate
variability. Estimated that probability of an
extreme summer such as that of 2003 has more than
doubled as a consequence of human-induced climate
change.
Source IPCC AR4 WGI Ch.9 p.696 (Hegerl et
al.,2007)
27
Projected changes in hydrological extremes
Source IPCC AR4 WGI Ch.10 (Meehl et al., 2007,
p.766)
28
New and enhanced storm risks?

• UK Met Office simulation suggested tropical
  storms may form off SE Brazil in 2070s
• In March 2004, Hurricane Catarina, the first S.
  Atlantic tropical storm, formed in this region

• Recent research suggests weakening of Tropical
  Easterly Jet may result in more tropical storms
  in Indian ocean, forming in monsoon season
  contrary to historical experience (Rao et al.,
  2008)

Source http//www.metoffice.gov.uk/weather/tropic
alcyclone/catarina.html
29
Climate change isnt just about more frequent
severe extremes.

• Global climate change will also cause long-term
  changes in climate, ecosystems, landscapes
  resource availability at regional scales

Source IPCC (2007)
30
Long-term climatic desiccation in North Africa
Simulations using A1B scenario. Top row Average
projected warming between 1980-1999 and
2080-2099, averaged over 21 models. Middle row
Fractional change in precipitation between
1980-1999 and 2080-2099, averaged over 21 models.
Bottom row number of models out of 21 that
project increases in precipitation.
Source IPCC AR4 WGI Ch.11 (Christensen et
al.,2007, p.869)
31
Glacial retreat water resources
Many glaciers set to disappear in next few
decades, e.g. Andean countries, Himalayas.
Projected warming by 2100 along American
Cordillera mountain chain, 8-model average, A2
scenario. Black triangles denote highest
mountains at each latitude white areas are below
land surface.
Sources Barnett et al., 2005 Bradley et al, 2007
32
Long-term sea-level rise
IPCC AR4 (2007)

• 1990s fastest recorded rise at 4mm per year

• IPCC (2007) projections of up to further 0.5 m
  by 21001

• omitted certain processes associated with ice
  sheet dynamics

More recent projections for 2100

• 1.4 m (Rahmstorf 2007)
• 0.8 - 2 m (Pfeffer et al 2008)
• 1 m (Rignot, in Kintisch 2009)

• Sea-level rise from ice sheet loss1
• Greenland 7 m
• West Antarctic 5 m
• Century to millennial timescales

References 1IPCC AR4 WGI Ch.10 (Meehl et al.,
2007)
33
Change will not necessarily be gradual

• May also be manifest through, large, abrupt,
  non-linear changes

34
Tipping elements in the Earths climate
Linked with large/abrupt changes in climate, more
likely for warming gt 2 C
Source Lenton et al., 2008, p. 1787
35
How likely are abrupt changes?

• Melting of Greenland Ice Sheet. Recently thought
  more-or-less inevitable, requiring 2.7 C local
  warming, but recently suggested may require 6 C
  increase in global mean temperature for complete
  melting. However, is losing mass rapidly. (See
  Kintisch, 2009.)
• Collapse of West Antarctic Ice Sheet. Unlikely
  this century but concerns about accelerated
  disintegration due to loss of fringing ice
  shelves (Meehl et al., 2007)
• Changes in Atlantic Deep Water Formation.
  Shutdown unlikely this century. Variety of
  problematic potential impacts but no mini ice
  age (Schiermeier, 2006)
• Indian Monsoon instability. Current models
  indicate strengthening increased variability,
  but some concerns about stability (Meehl et al.,
  2007 Zickfeld et al., 2005).
• Change in ENSO behaviour. Future behaviour of
  ENSO uncertain (Meehl et al., 2007).
• Loss of permafrost tundra. Already happening.
  More carbon in permafrost than estimated in 2007,
  large amounts of methane could be emitted (see
  Kintisch, 2009).
• Forest dieback. Warming drying appear to be
  contributing to accelerated tree mortality in
  northern hemisphere forests (van Mantgem et al.,
  2009).
• African monsoon changes Sahara greening. May
  already be happening. Response to increasing
  greenhouse gas concentrations uncertain (Brooks,
  2004).

1Kintisch, 2009
36
Amazon Collapse?

• Massive losses possible for warming gt 3 C 1,2
• Up to 40 loss suggested even for strong
  mitigation3
• Transition to savannah
• Positive feedback between deforestation, forest
  fragmentation, wildfire and increased drought
  frequency
• Large losses after 2005 drought4
• Loss of Amazon forest would amplify global warming

Evolution of climate and biomass over Amazon box
from 3 model simulations (HadCM3LC) with dynamic
vegetation. Continuous line fully coupled
climate-carbon cycle run. Dashed line run
without climate effects on the carbon cycle.
Stars run with prescribed, unmitigated (IS92a)
CO2 concentrations (from Cox et al., 2005)
1Betts et al (2004) 2Cox et al (2004) 3
Kintisch, 2009 4Philips et al. (2009) IPCC AR4
WGII Ch.4 (Fischlin et al., 2007)
37
Dunefield Remobilisation in Southern Africa
Greater Kalahari region - quiescent or fossil
dunes Thomas et al (2005) link dune mobility
index with climate model data in simulations
find

• significantly enhanced dune activityin the
  southern dunefield by 2039, and in the eastern
  and northern dunefields by 2069

• By 2099 all dunefields are highly dynamic, from
  northern South Africa to Angola and Zambia.

• Potential dune activity comparable with situation
  14-16,000 yrs ago during last arid phase.

• Changes due to reduced precipitation to
  evaporation ratio, increased wind speeds, loss of
  vegetation.

Source Thomas et al., 2005
38
Other long-term irreversible changes

• Loss of corals. By the time atmospheric partial
  pressure of CO2 will reach 560 ppm all coral
  reefs will cease to grow and start to dissolve.
  (Silverman et al., 2009)
• Changes in structure functioning of terrestrial
  and marine ecosystems. Substantial above 2 C,
  appreciable changes projected for 25-40 of
  ecosystems by 2100 with extensive forest
  woodland decline due (Fischlin et al., 2007)
• Changes in plant (including crop) productivity.
  Balance between temperature, rainfall CO2
  fertilisation effects (also changes in
  distribution and prevalence of pests diseases).
  Reduced productivity in some areas, increased in
  others (Easterling et al., 2007).
• Saltwater intrusion of coastal freshwater
  aquifers. Due to sea-level rise but exacerbated
  by subsidence caused by e.g. groundwater
  abstraction (Arnell et al., 2007).
• Permanent loss of coastal land including some
  low-lying inhabited islands. Exacerbated by
  accelerated coastal erosion due sea-level rise
  and more intense precipitation The
  unavoidability of sea-level rise, even in the
  longer-term, frequently conflicts with
  present-day human development patterns and trends
  (high confidence) Nicholls et al. (2007, p.317)

39
Conclusions

• Large, rapid changes in climate have occurred in
  the past
• Globally, the climate of the past 5000 years has
  been relatively stable
• This period of stability is now over

• The IPCC projections are looking increasingly
  conservative
• Prospects for keeping within agreed limits
  appear remote
• Warming likely to exceed anything seen for
  millions of years by 2100

• Many types of climatic extremes will become more
  frequent severe
• Long-term, perhaps severe, changes in landscapes
  resources can be expected

• Large emissions reductions are needed very soon
  to avoid worst impacts
• The less we mitigate, the harder will be the
  development challenge
• Business-as-usual is not sustainable
• Add-ons to development are not enough -
  different philosophy needed
• Development needs to reinvent itself to
  accommodate large climatic changes
• Development needs to be built around
  environmental variability limits if it is to be
  viable and successful

40
THE END
Source IPCC (2007)
41
References I

• Anderson K and Bows A (2008) Reframing the
  climate change challenge in light of post-2000
  emission trends. Philosophical Transactions of
  the Royal Society A. doi10.1098/rsta.2008.0138.
• Barnett, T. P., Adam, J. C. and Lettenmaier, D.
  P. 2005. Potential impacts of awarming climate on
  water availability insnow-dominated regions.
  Nature 438 303-309
• Betts, R. A., Cox, P. M., Collins, M., Harris, P.
  P., Huntingford, C. and Jones, C. D. 2007. The
  role of ecosystem-atmosphere interactions in
  simulated Amazonian precipitation decrease and
  forest dieback under global climate warming.
  Theor. Appl. Climatol. 78, 157-175.
• Bradley, R. S., Vuille, M., Diaz, H. F. and
  Vergara, W. 2006. Threats to Water Supplies in
  the Tropical Andes, Science 312 17551756.
• Brooks, N. 2004. Drought in the African Sahel
  long-term perspectives and future prospects.
  Tyndall Centre Working Paper No. 61
• Brooks, N. 2006. Cultural responses to aridity in
  the Middle Holocene and increased social
  complexity. Quaternary International 151 29-49
• Cox, P. M., Betts, R. A., Collins, M., Harris, P.
  P., Huntingford, C. and Jones, C. D. 2004.
  Amazonian forest dieback under climate-carbon
  cycle projections for the 21st century. Theor.
  Appl. Climatol. 78, 137-156
• de Menocal P, Ortiz J, Guilderson T et al. (2000)
  Abrupt onset and termination of the African Humid
  Period rapid climate responses to gradual
  insolation forcing. Quaternary Science Reviews
  19 347-361
• Fischlin, A., G.F. Midgley, J.T. Price, R.
  Leemans, B. Gopal, C. Turley, M.D.A. Rounsevell,
  O.P. Dube, J. Tarazona, A.A. Velichko, 2007
  Ecosystems, their properties, goods, and
  services. Climate Change 2007 Impacts,
  Adaptation and Vulnerability. Contribution of
  Working Group II to the Fourth Assessment Report
  of the Intergovernmental Panel on Climate Change,
  M.L. Parry, O.F. Canziani, J.P. Palutikof, P.J.
  van der Linden and C.E. Hanson, Eds., Cambridge
  University Press, Cambridge, 211-272.
• Gohar, L. K. and Shine, K. P. 2007. Equivalent
  CO2 and its use in understanding the climate
  effects of increased greenhouse gas
  concentrations. Weather 62 307-311

42
References II

• Haywood, A., Bonham, S., Hill, D. et al. 2009.
  Lessons of the mid-Pliocene Planet Earthís last
  interval of greater global warmth IOP Conf.
  Series Earth and Environmental Science 6 (2009)
  072003 doi10.1088/1755-1307/6/7/072003
• Hegerl, G.C., F. W. Zwiers, P. Braconnot, N.P.
  Gillett, Y. Luo, J.A. Marengo Orsini, N.
  Nicholls, J.E. Penner and P.A. Stott, 2007
  Under- standing and Attributing Climate Change.
  In Climate Change 2007 The Physical Science
  Basis. Contribution of Working Group I to the
  Fourth Assessment Report of the Intergovernmental
  Panel on Climate Change Solomon, S., D. Qin, M.
  Manning, Z. Chen, M. Marquis, K.B. Averyt, M.
  Tignor and H.L. Miller (eds.). Cambridge
  University Press, Cambridge, United Kingdom and
  New York, NY, USA.
• IPCC, 2007 Summary for Policymakers. In Climate
  Change 2007 The Physical Science Basis.
  Contribution of Working Group I to the Fourth
  Assessment Report of the Intergovernmental Panel
  on Climate Change Solomon, S., D. Qin, M.
  Manning, Z. Chen, M. Marquis, K.B. Averyt,
  M.Tignor and H.L. Miller (eds.). Cambridge
  University Press, Cambridge, United Kingdom and
  New York, NY, USA.
• Jansen, E., J. Overpeck, K.R. Briffa, J.-C.
  Duplessy, F. Joos, V. Masson-Delmotte, D. Olago,
  B. Otto-Bliesner, W.R. Peltier, S. Rahmstorf, R.
  Ramesh, D. Raynaud, D. Rind, O. Solomina, R.
  Villalba and D. Zhang, 2007 Palaeoclimate. In
  Climate Change 2007 The Physical Science Basis.
  Contribution of Working Group I to the Fourth
  Assessment Report of the Intergovernmental Panel
  on Climate Change Solomon, S., D. Qin, M.
  Manning, Z. Chen, M. Marquis, K.B. Averyt, M.
  Tignor and H.L. Miller (eds.). Cambridge
  University Press, Cambridge, United Kingdom and
  New York, NY, USA.
• Kerr, R. 2005. Millenniums Hottest Decade
  Retains Its Title,for Now. Science 307 828-829.
• Kintisch, E. 2009. Projections of Climate Change
  Go From Bad to Worse, Scientists Report. Science
  326 (20 March 2009 ) 1546-1547.
• Lenton, T., Held, H., Kriegler, E., Hall, J.,
  Lucht, W., Rahmstorf, S. and Schellnhuber, H-J.
  2008. Tipping elements in the Earths climate
  system. Proceedings of the National Academy of
  Sciences 105 1786-1793.

43
References III

• Meehl, G.A., T.F. Stocker, W.D. Collins, P.
  Friedlingstein, A.T. Gaye, J.M. Gregory, A.
  Kitoh, R. Knutti, J.M. Murphy, A. Noda, S.C.B.
  Raper, I.G. Watterson, A.J. Weaver and Z.-C.
  Zhao, 2007 Global Climate Projections. In
  Climate Change 2007 The Physical Science Basis.
  Contribution of Working Group I to the Fourth
  Assessment Report of the Intergovernmental Panel
  on Climate Change Solomon, S., D. Qin, M.
  Manning, Z. Chen, M. Marquis, K.B. Averyt, M.
  Tignor and H.L. Miller (eds.). Cambridge
  University Press, Cambridge, United Kingdom and
  New York, NY, USA.
• Nakicenovic, N., and R. Swart (eds.), 2000
  Special Report on Emissions Scenarios. A Special
  Report of Working Group III of the
  Intergovernmental Panel on Climate Change.
  Cambridge University Press, Cambridge, United
  Kingdom and New York, NY, USA, 599 pp.
• Peltier, W. R. 2002. On eustatic sea level
  history Last Glacial Maximum to Holocene.
  Quaternary Science Reviews 21 377-396
• Pfeffer, W. T., Harper, J. T. and ONeel, S.
  2008. Kinematic Constraints on Glacier
  Contributions to 21st-Century Sea-Level Rise.
  Science 321 1340-1343.
• Phillips, O.L., Aragão, L. E. O. C., Lewis, S. L.
  et al. 2009. Drought Sensitivity of the Amazon
  Rainforest. Science 323 1344-1347.
• Pittock, AB (2008) Ten reasons why climate change
  may be more severe than projected, in McCraken,
  M. C., Moore, F. and Tapping, J. C. (eds.) Sudden
  and Disruptive Climate Change Exploring the Real
  Rsisk and How We Can Avoid Them, pp.11-27.
  Earthscan, London
• Schiermeier, Q. 2006. A sea change. Nature 439
  256-260.
• Rahmstorf, S. 2007. A Semi-Empirical Approach to
  Projecting Future Sea-Level Rise. Science 315
  368-370.
• Rao, V. B., Ferreira, C. C., Franchito, S. H.,
  Ramakrishna, S. S. V. S. 2008. In a changing
  climate weakening tropical easterly jet induces
  more violent tropical storms over the north
  Indian Ocean
• Silverman, J., B. Lazar, L. Cao, K. Caldeira, and
  J. Erez (2009), Coral reefs may start dissolving
  when atmospheric CO2 doubles, Geophys. Res.
  Lett., 36, L05606, doi10.1029/2008GL036282.

44
References IV

• Somerville, R., H. Le Treut, U. Cubasch, Y. Ding,
  C. Mauritzen, A. Mokssit, T. Peterson and M.
  Prather, 2007 Historical Overview of Climate
  Change. In Climate Change 2007 The Physical
  Science Basis. Contribution of Working Group I to
  the Fourth Assessment Report of the
  Intergovernmental Panel on Climate Change
  Solomon, S., D. Qin, M. Manning, Z. Chen, M.
  Marquis, K.B. Averyt, M. Tignor and H.L. Miller
  (eds.). Cambridge University Press, Cambridge,
  United Kingdom and New York, NY, USA.
• Thomas D. S. G., Knight, M. And Wiggs, G. F. S.
  2005 Remobilization of southern African desert
  dune systems by twenty-first century global
  warming. Nature 435, 1218-1221.
• Trenberth, K.E., P.D. Jones, P. Ambenje, R.
  Bojariu, D. Easterling, A. Klein Tank, D. Parker,
  F. Rahimzadeh, J.A. Renwick, M. Rusticucci, B.
  Soden and P. Zhai, 2007 Observations Surface
  and Atmospheric Climate Change. In Climate
  Change 2007 The Physical Science Basis.
  Contribution of Working Group I to the Fourth
  Assessment Report of the Intergovernmental Panel
  on Climate Change Solomon, S., D. Qin, M.
  Manning, Z. Chen, M. Marquis, K.B. Averyt, M.
  Tignor and H.L. Miller (eds.). Cambridge
  University Press, Cambridge, United Kingdom and
  New York, NY, USA.
• Van Mantgem, P. J., Byrne, J. C., Daniels, L. D.
  et al. Widespread Increase of Tree Mortality
  Rates in the Western United States. Science 323
  521-524.
• Vernet, R., Faure, H. (2000) Isotopic chronology
  of the Sahara and the Sahel during the late
  Pleistocene and the early and Mid-Holocene
  (15,0006000 BP)., Quaternary International
  6817 385387.
• Warren, R. (2006). Impacts of Global Climate
  Change at Different Annual Mean Global
  Temperature Increases, in Schellnhuber, H.J.,
  Cramer, W., Nakicenovich, N., Wigley, T., and
  Yohe, G. (Eds) Avoiding Dangerous Climate Change,
  Cambridge University Press.
• Wunsch, C. 2009. A Perpetually-Running ENSO in
  the Pliocene? Journal of Climate. DOI
  10.1175/2009JCLI2925.1
• Zickfeld, K., Kopf, B., Petoukhov, V.,
  Schellnhuber, H. J. 2005. Is the Indian summer
  monsoon stable against global change?.
  Geophysical Research Letters 32, L15707,
  doi10.1029/2005GL022771