the natural and anthropogenic concepts of contemporary climate warming

ISSN 1019�3316, Herald of the Russian Academy of Sciences, 2013, Vol. 83, No. 2, pp. 150–157. © Pleiades Publishing, Ltd., 2013.Original Russian Text © D.G. Zamolodchikov, 2013, published in Vestnik Rossiiskoi Akademii Nauk, 2013, Vol. 83, No. 3, pp. 227–235.

150

With regard to the influence on the global publicopinion, politics, and economy, global warming iswithout equal among environmental problems. In1992, the UN Framework Convention on ClimateChange (UN FCCC) was developed, fixing the mainprovisions of climate policy: the current warming tellsnegatively on the existence of society and nature; themain cause of warming is the growing concentration ofatmospheric greenhouse gases; this growth is deter�mined by the increase in anthropogenic emissions,primarily, from fossil fuel combustion; and the task ofmaintaining the global climate requires a decrease inanthropogenic greenhouse gases emissions [1]. Tovarying degrees of detail, the above provisions have cir�culated in tens of thousands of scientific publications.The most consistent and comprehensive considerationof the anthropogenic warming concept is provided bythe assessment and special reports of the Intergovern�mental Panel on Climate Change (IPCC) [2, 3, etc.].

Climate warming�related problems are invariablyin the focus of mass media, such information oftentending to promote sensation or even scandal. Sufficeit to recall the “Climategate” of 2009, caused by thehacking of an archive with correspondence and pre�liminary data�processing results at the ClimaticResearch Unit at the University of East Anglia. Thepublished correspondence included the exchange ofviews on a number of climate change�related issuesbetween prominent IPCC researchers. The presenceof such issues gave a lever to mass media for criticizingthe Intergovernmental Panel on Climate Change andaccusing it of biased data presentation and hidinginformation about the real climatic situation.

Criticism of the anthropogenic concept in generaland IPCC conclusions in particular is present not only

in mass media but also in scientific publications, theauthors of which are serious experts in different scien�tific areas. For example, a series of works by a group ofresearchers at the Arctic and Antarctic Research Insti�tute (AARI) [4] connects the modern temperaturedynamics with the presence of two natural 60�year and200�year cycles. The cycle formation mechanisminvolves the planet’s wind field, namely, so�called cir�cumpolar vortexes that determine western–eastern airtransports in the middle�latitude troposphere. The60�year cycle is connected with changes in the inten�sity of the vortexes (they become deeper during warm�ing), while the 200�year one is due to modifications intheir spatial position (under warming, they becomewider). The external cause of the emergence of cyclic�ity is connected with the rhythm of solar activity, therebeing a 20� to 25�year phase shift between the seculardynamics of sunspots and the state of circumpolar vor�texes. According to the cited works, the addition ofcyclical components at the boundary of the 20th and21st centuries has already led to the replacement ofwarming by cooling, which is confirmed by the ten�dency toward a decrease in global temperature in thesecond half of the 2000s. Similar views are shared by anumber of other researchers [5, 6], although they varyconsiderably in singling out solar rhythm periods anddescribing mediator climatic mechanisms.

At present, decision makers and other stakeholdershave to choose between two opposing concepts(anthropogenic warming and natural climatic cyclic�ity), the significance of the choice being very high.Should we decrease industrial greenhouse gas emis�sions, which will inevitably increase economic expen�ditures, or is this an expensive but useless struggleagainst cosmic�scale natural factors? Is it necessary tomodify plans on the economic development of north�ern regions in connection with the degradation of thepermafrost and the Arctic Ocean ices, or, rather,should we develop land transport systems under cool�

Environmental Problems

Global warming is one of the most discussed environmental problems. Greenhouse gas emission trading sys�tems are actively functioning, and many countries are developing programs on adapting to the new climaticconditions. Note that global temperature growth rates in the 21st century have decreased, and the voices ofthe opponents of the global anthropogenic warming concept have become louder. Whom should we believe—the adherents of global warming or its opponents? What should we get ready for—the heat or the cold?

DOI: 10.1134/S1019331613010140

The Natural and Anthropogenic Conceptsof Contemporary Climate Warming

D. G. Zamolodchikov*

* Dmitrii Gennad’evich Zamolodchikov, Dr. Sci. (Biol.), is aleading researcher at the RAS Center for Forest Ecology andProductivity and head of the Department of General Ecology ofthe Faculty of Biology at Moscow State University.

HERALD OF THE RUSSIAN ACADEMY OF SCIENCES Vol. 83 No. 2 2013

THE NATURAL AND ANTHROPOGENIC CONCEPTS 151

ing? To which should we adapt agriculture and for�estry, to the heat or to the cold?

The target of this article is to analyze comparativelythe degree of conformance of the alternative climatechange concepts to the existing data on global temper�ature dynamics. This comparison will be implementedthrough simple statistical data processing techniques.Note that this work is not targeted at proving an a pri�ori chosen concept by all means, and the conclusionsmade are consequences of balanced analysis. Thisapproach makes this work different from the majorityof works on similar problems, whose authors choosetheir position in advance, which leads to increasedapologetics of their own views and expressed criticismof the alternative concept.

* * *

The main initial sources were the of the Oak RidgeCarbon Dioxide Information Analysis Center’s dataon global temperature anomalies over 1850–2010 [7],historical data on atmospheric CO2 concentrationdynamics over 1850–1958 [8], and the monitoringdata of the National Oceanic and AtmosphericAdministration (Boulder, US) on atmospheric CO2

concentration at the Mauna Loa station [9]. Note thatboth adherents and opponents of the anthropogenicwarming concept do not question the correctness ofthe cited data sets and refer the differences to interpre�tation. During the subsequent processing, data ontemperature anomalies were recalculated into annualaverage centigrade temperature values. Additionalinformation used in interpreting the elucidated ten�dencies and performing prediction calculations is pre�sented in the NOAA (National Oceanic and Atmo�spheric Administration) Paleoclimatology Recon�structions Network (Boulder) [10], in the data of theCarbon Dioxide Information Analysis Center (OakRidge) on fossil fuel combustion [11], and in the IPCCforecast scenarios of anthropogenic emissions andatmospheric CO2 concentrations [12].

Statistical data processing consisted of buildingnonlinear regression models by the method of leastsquares using the Statistica 6.1 package (Stat Soft Inc.,United States). Nonlinear estimator procedures undercomplex forms of the equations analyzed and a highdispersion of the initial data may lead to the detectionof several local minima of residual dispersion. To findthe equation with the lowest residual dispersion value,we performed calculations with different sets of startupparameter values. We included in the final form onlythe parameters whose significance level correspondedto P ≤ 0.05 (except for one specified case). In perform�ing regression estimation, we did not use any tech�niques associated with the initial fixation of individualparameter values.

Considering the dynamics of surface air globaltemperature over the period from 1850 through 2010(Fig. 1) makes it possible to elucidate a number of spe�cific features. First, this is the expressed tendencytoward temperature growth in 1910–2010. This ten�dency underlies the formation, starting from the early1970s, of the anthropogenic warming concept and thesubsequent development of the system of measures toprevent warming. Remember that, according to theanthropogenic warming concept, the trend toward thegrowth of global temperature is explained by theincrease in the concentration of carbon dioxide andother greenhouse gases in the atmosphere. The secondcharacteristic feature of the dynamics is the local tem�perature maximum that fell on the 1940s. The lessexpressed maxima in the 1880s and, to all appear�ances, the first half of the 2000s are also noteworthy.Advocates of the natural change concept explain thepresence of these three maxima as a manifestation ofthe 60� and 70�year cycles [4, 5]. The third character�istic trait, which manifests itself on the line of the 5�year moving average cycle, is the fixation of local tem�perature maxima with a periodicity of approximately11 years. This feature is explained by the 11�year solarcycle. Note that studies on the connection of weathervariations with this cycle have a long�standing history,and the connections themselves are reliably estab�lished in modern works on the energy balance of theearth’s atmosphere [13, etc.].

Let us share the point of view of adherents of theanthropogenic warming concept first and propose anequation that can reproduce the specified features ofthe global temperature dynamics. Let us take intoaccount that the dependence of temperature on CO2

concentration is nonlinear. The point is that the mainband of long�wave spectrum absorption by CO2 mole�cules is limited to 4.2–4.3 µm. This band becomesexhausted even at small CO2 concentrations in the air.If the concentration of this gas increases, radiation

13.4

1850 1870

Temperature, °C

1

13.21890 1910 1930 1950 1970 1990 2010

13.6

13.8

14.0

14.2

14.4

14.6

2

Fig. 1. Average annual global temperature dynamics over1850–2010.(1) Data of instrumental measurements [7]; (2) the five�year moving average value.

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ZAMOLODCHIKOV

absorption grows at the expense of the band’s edgeparts (wings), but the farther from the main band, theless effectively CO2 molecules confine radiation.Thus, the ability of carbon dioxide to restrain longwave radiation decreases as its atmospheric concentra�tion grows, which leads to a logarithmic connectionbetween the greenhouse effect and CO2 concentra�tion. With account for this fact, we may propose thefollowing equation to describe global temperaturedynamics:

(1)

where Т is the average global temperature, °С; CO2 isthe carbon dioxide concentration in the atmosphere,ppm; Y is the serial year number; and a, b, с1, c2, c3, d1,d2, and d3 are parameters. All the parameters have aclear physical interpretation: а is the average globaltemperature with no account for the greenhouseimpact of carbon dioxide, °С; b is the greenhouseeffect in the Napierian logarithm of carbon dioxideconcentration, °С ppm–1; c1 and d1 mean the semir�ange of the oscillations of the two cyclical processes,°С; c2 and d2 mean the phase shift of the cycle relativeto the beginning of the starting year number; and c3

and d3 are characteristics of the period of the cycles(a period expressed in years equals the ratio of 2π to c3

or d3).

Initial information on the dependent T and one ofthe independent Y variables of equation (1) is pre�sented in Fig. 1. The dynamics of the second indepen�dent variable (CO2) is shown in Fig. 2. This value ischaracterized by accelerating growth from 287 ppm in1850 to 390 ppm in 2010. This growth is caused byanthropogenic carbon dioxide emission, primarilyconnected with fossil fuel combustion and supple�mented by changes in land use (deforestation), as wellas by agriculture (humus losses in arable soils). Some

( )

( )

= + + +

+ +

2ln CO sin с с

sin1 2 3

1 2 3

( )

,

T a b c Y

d d d Y

works indicate that the present growth of CO2 concen�tration is determined by its emission from the oceansbecause an increase in water temperature decreasesthe solubility of carbon dioxide [14]. This thesis is wideopen to criticism. Suffice it to compare the yearly val�ues of anthropogenic emissions and those of changesin the atmospheric СO2 reserve, expressed in similarunits (Fig. 2). The change in the atmospheric CO2

reserve is two times less than the annual anthropogenicemission; consequently, the global natural environ�ment, including the oceans, land surface, and theupper shells of the lithosphere, is a sink of atmosphericcarbon rather than its source. The picture of globalcarbon dioxide sinks and sources is considered indetail in both IPCC reports [2] and numerous scien�tific publications [15, 16, etc.].

Let us perform the regression estimation of theparameters of equation (1):

(2)

Equation (2) describes 86.6% of the initial data dis�persion, which is a very good indicator for regressiondependences found on natural materials. The regres�sion as a whole and all the parameters of equation (2)are statistically significant for P ≤ 0.02. The depen�dence reproduces all the above�mentioned features ofglobal temperature dynamics (Fig. 3a), such as thetrend toward increase and the cycles with a periodicityof 10.5 years (solar cycle) and 68.8 years (circumpolarvortex cyclicity). Note that the cyclicity parametersare established in the process of regression analysis;i.e., the discovered cycles describe the maximal sharesof the variation in the initial data compared to pro�

( )

( )

( )

= − +

− +

+

= < =

2

2

2 46 2 82ln CO

1 1sin 15 7 914

247sin 6

866 1 161

. .

0. 0 . 0.0

0.0 0. 00 ,

0. , 0.0 , .

T

Y

Y

R P n

275

1850 1870

Co

nce

ntr

atio

n C

O2,

pp

m

1

2501890 1910 1930 1950 1970 1990 2010

300

325

350

375

400

2

4

31

Em

issi

on

s an

d r

eser

ve c

han

ge,

Gt

C/y

r−1

3

5

7

9

−1

Fig. 2. Dynamics of atmospheric CO2 concentration [8, 9], anthropogenic CO2 emissions [11], and the change in the atmo�spheric CO2 reserve over 1850–2010.(1) Concentration; (2) emissions; and (3) and (4) annual values and ten�year moving average change in the reserve.



cesses with another periodicity, which may potentiallybe involved in global temperature dynamics. Thephase parameter of the 10.5�year cycle was rejectedbecause of its statistical insignificance (P = 0.19). Theoscillation range of the 69�year cycle is approximately0.202°C, while that of the 10.5�year one is 0.049°C; inother words, these components explain a part of theinitial data variation but cannot be used to study cli�matic trends higher than 0.251°C.

According to equation (2), the greenhouse effect ofthe CO2 concentration natural logarithm is2.82°C ppm–1. We get that in 1850 the greenhouseeffect of CO2 reached 16.0°C, while today it is 16.9°C;i.e., it has increased by 0.86°C. According to [17, 18],the share of carbon dioxide in the 33°C of the totalgreenhouse effect is 7–8°C, i.e., 23–25%. The CO2

greenhouse effect evaluation that follows from equa�tion (2) exceeds this value by two times. To explain thisdiscrepancy, it is necessary to account for the fact thatthe climatic system has numerous feedbacks, particu�larly between temperature and the content of watervapor (note that the contribution of this greenhousegas is dominant), temperature and albedo (snow coverwidening under cooling), and so on. The change inCO2 concentration affects the above interconnections,and, hence, its action on temperature grows. Therecent GISS (Goddard Institute for Space Studies)general circulation model–based experiments showthat, under the hypothetical full removal of carbondioxide from the earth’s atmosphere, its average tem�perature will decrease down to –21°C during the next50 years; i.e., it will be even lower with the entirepresent greenhouse effect removed. In the context ofthese data, the estimate of the earth’s average globaltemperature at a zero greenhouse contribution,derived from equation (2) and equaling –2.46°C,appears quite moderate.

Let us now adopt the point of view of adherents ofthe natural concept of climate change and formulateequations that do not include CO2 concentration inthe scope of independent variables. S.�I. Akasofu [8]considers two natural components of climate change:the linear trend of recovery after the Little Ice Agefrom 1400 through 1800 and the multidecadal oscilla�tion with a periodicity of about 60 years [6]. The citedwork, available on the University of Alaska’s websitebut still unpublished in a peer�reviewed journal, notesthat the above natural factors are quite sufficient todescribe temperature dynamics for 1880–2007. Let usverify this thesis for the extended (compared to the ini�tial work) time series of 1850–2010. Let us modifyequation (1) by substituting the CO2 concentrationlogarithm with the serial number of the year (this sub�stitution reproduces the linear trend of “recovery fromthe Little Ice Age”), both cyclic components remain�ing in place. Akasofu’s initial model includes the linearcomponent and only one cyclic component; the inclu�

sion of the second component ensures the similarity ofthe equations under analysis. After performing regres�sion analysis, we get the following equation:

(3)

Regression (3) is statistically significant, but thedegree of initial dispersion description compared toequation (2) is somewhat worse (R2 = 0.789). Theparameters are significant for P ≤ 0.03 in the case whenwe do not take into account the semirange of the 10.5�year cycle (P = 0.17). As an exception, this parameteris preserved in the regression equation; otherwise, we

( )

( )

= +

− +

+

= < =2

5 3 453

138sin 1 945

187sin 6

789 1 161

.0 0.00

0. 0.0 0.0

0.0 0. 00 ,

0. , 0.0 , .

T Y

Y

Y

R P n

13.4

1850 1870

Temperature, °C

(c)

13.21890 1910 1930 1950 1970 1990 2010

13.6

13.8

14.0

14.2

14.4

14.6

13.4

1850 1870

(b)

13.21890 1910 1930 1950 1970 1990 2010

13.6

13.8

14.0

14.2

14.4

14.6

13.4

1850 1870

(a)

13.21890 1910 1930 1950 1970 1990 2010

13.6

13.8

14.0

14.2

14.4

14.6

1

2

Fig. 3. Model simulations of global temperature dynamics.(a) Account for the linear connection with the CO2 con�centration logarithm and two cycles (10.5 and 68.8 years);(b) account for the linear connection with the number ofthe year and two cycles (10.5 and 66.5 years); (c) accountfor three cycles (10.5, 60.2, and 229.8 years); (1) data ofinstrumental measurements [7]; and (2) simulation.

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ZAMOLODCHIKOV

would have to withdraw the entire short�period com�ponent. Equation (3) reproduces both cyclic pro�cesses, but there are certain problems with regard todescribing the trend toward an increase in temperature(Fig. 3b), namely, the underestimation of tempera�tures in 1850–1860 and 2000–2010.

The work by the research team at the Arctic andAntarctic Research Institute [19] interprets the trendtoward temperature growth as a consequence of the200�year cyclic process, specified in the original bytwo linear components: rising in 1850–2000 and fall�ing after 2000. To verify the hypothesis about the con�tribution of the 200�year cycle, we use a modificationof equation (3), where the linear component is substi�tuted by a third cyclic process. In this case, regressionanalysis leads to equation (4):

(4)

Just like the previous ones, equation (4) is statisti�cally significant. With regard to the degree of initialdata dispersion description, it surpasses equation (3)but is inferior to equation (2). All the parameters aresignificant at P ≤ 0.05. The third cyclic component hasa period of 229 years and a range of 0.603°C. The addi�tion of the three cyclic components may yield warmingby 0.911°C at best, after which cooling begins. Con�sidering the correctness of the description of tempera�ture dynamics by time intervals in equation (4)(Fig. 3c), we see an underestimation in 2000–2010.

We must state that the statistical analysis of globalair�temperature dynamics data for 1850–2010 doesnot allow us to make a clear choice between theanthropogenic warming concept and the naturalwarming one. Regression as a whole and the majorityof the parameters of equations (2)–(4) are significantunder a low P, while the R2 superiority of equation (2)

( )

= −

− − +

+

= < =2

13 8 3 2sin 24

131sin 9 4 1 4

222sin 6

852 1 161

. 0. 0 (0.0 )

0. ( . 0 0. 0 )

0.0 0. 00 ,

0. , 0.0 , .

T Y

Y

Y

R P n

compared to equations (3) and (4) is not very high.The underestimation of temperature values in 2000–2010 by equations (3) and (4) may be explained merelyas a manifestation of residual data dispersion; in anycase, it does not appear exceptional compared to otherdecades. Thus, both adherents and opponents of theanthropogenic warming concept should not beaccused of an incorrect interpretation of the existingdata: the point is that, over the time interval underconsideration, any independent variable showing anapproximately even tendency toward growth will dem�onstrate a statistically valid connection with thegrowth of global temperature. Alone, this thesis con�firms equation (3), where the trend is specified by asimple linear connection with the serial number of theyear. Hence, to choose between the concepts, it is nec�essary to consider an additional set of data (paleocli�matic reconstructions).

At present, there are quite a number of paleocli�matic reconstructions based on the analysis of tree�ring series, glacier stratification, coral growth rates,and information provided by historical documents.Let us use the fullest (with respect to the initial dataset) reconstruction of the global (land and oceanic)temperature dynamics for the period from 500 through1995 [20]. Let us restrict the period under consider�ation to the interval from 500 through 1900 (Fig. 4);i.e., the interval in which the potential anthropogenicimpact on climate is negligibly small. The visual anal�ysis of the dynamics elucidates the presence of a long�term change with the maximum in 600–900 and theminimum in 1500–1800. The minimum coincideswith the Little Ice Age. In addition, we observe varia�tions with periods of several tens or hundreds of years,but their visual identification is difficult. Let us per�form regression analysis with the objective to findthree cyclic components that would maximally explainthe variation in the initial data. In the Statistica 6.1package used, the number of cases included in theregression estimation cannot exceed 500. Hence, letus select from the full reconstruction data at a pitch ofthree years (500, 503, and so on up to 1901) and per�form a nonlinear estimation:

(5)

Equation (5) explains 67.8% of the initial data dis�persion, and all the parameters (including the phases)are significant at P ≤ 0.02. The equation identifiesthree cyclic components with periods of 1759, 207,and 65 years. Note that the initial climatic reconstruc�tion is represented by values of the ten�year movingaverage; this is why it is fundamentally useless for sin�gling out the 10.5�year short�period cycle. For thesame reason, the reduction of the sampling used in the

( )

= − − +

− − +

− +

= < =2

13 7 193sin 1 35 357

622sin 852 3 3

266sin 3 55 973

678 1 468

. 0. ( . 0.00 )

0.0 ( 0. 0.0 0 )

0.0 . 0.0 ,

0. , 0.0 , .

T Y

Y

Y

R P n

13.4

500 700

Temperature, °C

1

13.2900 1100 1300 1500 1700 1900

13.6

13.8

14.0

14.2

2

Fig. 4. Reconstruction of global temperature dynamicsfrom 500 through 1900.(1) [20]; (2) its simulation by equation (5).



analysis down to 33.3% from the initial one has no sig�nificant effect on the final regression result.

The components of 65 and 207 years may becompared with the timewise close cycles from equa�tions (2)–(4). However, the cycle’s phase is of signifi�cance here. Figure 5 compares different cyclic compo�nents of equations (2), (4), and (5) by their potentialcontribution on the interval from 1990 through 2010.The component of 69 years from equation (2) and thecomponent of 65 years from equation (5) are close inphase but different in amplitude. The closeness of thephases of the cycles under discussion makes it possibleto conclude that the presence of a cyclic componentwith a period of about 65–70 years is not refuted bypaleoclimatic data.

Another situation is with the 230�year cycle thatexplains the trend toward the current temperatureincrease in equation (4). By phase, it does not coincideat all with the cycle of 207 years from equation (5) (seeFig. 5). Consequently, the paleoclimatic retrospectivedoes not confirm the presence of a 200�year climaticcycle with a phase position that could lead to constanttemperature growth in 1900–2000. Moreover, thevisual analysis of the retrospective does not allow us toidentify cyclic processes with a period of about200 years, the amplitude of which would be 0.6°C, asis the case in equation (4). Variations of similar ampli�tudes are observed either on large (thousand years) oron smaller (decades) time intervals.

Climatic reconstruction makes it possible to verifythe hypothesis about the presence of the linear “recov�ery�from�the�Little�Ice�Age” [6] trend that underliesequation (3). For 1800–1900, a statistically significant(P < 0.01) linear trend toward temperature increase(0.00231°C/year) is established. The analogous valuefrom equation (3) is 0.00453°C/year, i.e., two timeshigher. The average temperature difference betweenthe coldest (1500–1800) and the warmest (600–900)periods is 0.39°C. With account for climate warmingby 0.23°C over the 19th century, only 0.13°C remainsfor the 20th century for recovery from the Little IceAge, while the real temperature growth was about0.65°C. Thus, the analysis of the climatic reconstruc�tion does not confirm the hypothesis about the pres�ence of a linear global temperature trend that wouldhave characteristics able to explain modern warming.

Note the long�period component—1759 years—that appears in equation (5). It has quite a large ampli�tude (0.39°C) and determines the change from thewarm interval in 600–900 to the Little Ice Age in1500–1800. However, its contribution to modernwarming is extremely small due to the length of itsperiod (see Fig. 5). Most likely, the long�period com�ponent under discussion is determined by the 2000�year cycle of solar activity, called the Hallstatt cycle[21]. Together with the above�mentioned 10.5�yearSchwalbe cycle, these are the most clearly identified

harmonic oscillations of the Sun. Also singled outamong oscillations are the 88 (70–100)�year Gleiss�berg cycle, the 211�year Suess cycle, and a number ofothers [21, 22], although astrophysicists have notformed an agreed position concerning the composi�tion and periodicity of the decadal and secular solarcycles thus far. There is the opinion [23] that solaroscillations with such periodicity are absent alto�gether, while average period minima and maxima ofactivity are determined by stochastic processes. Let usadd that the retrospective of global temperaturedynamics (see Fig. 5) confirms this point of viewrather than refutes it.

* * *

The performed analysis of retrospective data onglobal temperature dynamics shows that, on the timeinterval from 500 through 1900, there were no cyclicprocesses with such a combination of periodicity andamplitude that could lead to the warming observed inthe 20th century; consequently, it cannot be explainedwithout involving the anthropogenic factor. Note thatthis conclusion is contained and substantiated in detailin the IPCC Fourth Assessment Report [2]. However,we should not ignore natural cyclicity because it deter�mines a number of specific features of modern cli�matic dynamics by either decreasing or increasingtemperature change rates.

Having chosen equation (2), which includes boththe directed anthropogenic and the cyclic naturalcomponents, let us use it to forecast the dynamics ofglobal temperature in the 21st century. To forecast it, itis necessary to have a scenario of changes in CO2 con�centration in the atmosphere, which, in turn, dependson the future dynamics of anthropogenic emissionsand various responses of the natural environment. Thefuture dynamics is determined by many factors, suchas, in particular, technological processes (especiallywith regard to alternative forms of energy), world

−0.2

1900

Temperature, °C

1

−0.31920

−0.1

0

0.1

0.2

0.3 2

1940 1960 1980 2000

34 5

Fig. 5. Potential contribution of cyclic components to theglobal temperature dynamics over 1900–2010.(1) 69 years from equation (2); (2) 230 years from equa�tion (4); (3, 4, and 5) 65, 207, and 1759 years from equa�tion (5), respectively.

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ZAMOLODCHIKOV

economy development rates, success or failure in theactivity targeted at elaborating new internationalagreements on climate, and so on. Both the above�mentioned and other factors were accounted for by theIntergovernmental Panel on Climate Change in devel�oping anthropogenic emission scenarios [24], whichwere later used in numerous works on predictive mod�eling of the global climate. For our forecast, we usescenarios A2, A1B, and B1 (Fig. 6a) or, more precisely,

forecast estimates of CO2 concentration in the atmo�sphere according to these scenarios [12]. The forecastmay be performed on the basis of equation (2) usingCO2 concentrations (Fig. 6b) and the respective serialnumbers of the year as independent variables. Sincethe initial data on CO2 concentrations [12] are avail�able with a pitch of ten years, the discovered forecastestimates of temperature (Fig. 7) do not reproduce the10.5�year cycle or an accurate position of the extremaof the 69�year cycle. Nevertheless, we should payattention to the deceleration of temperature growth in2020–2040, explained by the contribution of thedescending arm of the 69�year cyclic component.However, this component cannot any longer ensuresustainable cooling for a couple of decades (analogousto the situation in 1950–1970) under the growth ofanthropogenic emissions according to the assumedscenarios.

Under the most severe scenario A2, by 2100, theCO2 concentration will reach 836 ppm and the averageglobal temperature, +16.5°C. In other words, over the21st century, warming will reach +2.2°C. For the A1Band B1 scenarios, temperature growth over this cen�tury is 1.8 and 1.0°C, respectively. Since all the param�eters of equation (2) have a clear physical meaning andare identified sufficiently accurately by empirical data,the reliability of this forecast should be assessed as veryhigh.

The forecast presented in the IPCC Fourth Assess�ment Report [2], based on coupled atmosphere–ocean general circulation models (AOGCM), yieldedthe following estimates of temperature growth in the21st century for the A2, A1B, and B1 scenarios: 3.6,2.8, and 1.8°C, respectively. These values are 1.5–1.6times higher than those obtained from equation (2).However, the expressed sensitivity of one of theAOGCM components to CO2 concentrations in theatmosphere was mentioned above in discussing thecontribution of this gas to the greenhouse effect. Let usadd that the quoted assessments are average for the setof models. Our estimates correspond to the lower limitof the range of the AOGCM forecast values; i.e., someof the models yield results analogous to those obtainedfrom equation (2).

The significance of the discrepancies between ourforecast and the averaged AOGCM assessment is highin connection with the widespread opinion that, toprevent dangerous changes, warming should be lim�ited to 2°C compared to the preindustrial epoch. Thisthesis has been discussed actively at the latest UNFCCC conferences of the parties, and it will probablybe included in future climate agreements. The morerapidly temperature “responds” to CO2 concentrationgrowth, the more considerable efforts we should maketo reduce emissions to reach the goal, 2°C. Accordingto the AOGCM averaged forecast [2], under the A2and A1B emission scenarios, the 2°C boundary will be

2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

(b)850

750

650

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CO2 concentration, ppm

2000 2010 2020 2030 2040 2050 2060 2070 2080 2090 2100

(a)30

10

5

0

Emissions, GtC/yr

25

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Fig. 6. (a) IPCC�proposed scenarios of anthropogenicCO2 emissions and (b) predicted changes in CO2 concen�trations [12]: (1, 2, and 3) scenarios A2, A1B, and B1,respectively.

2000 2020 2040 2060 2080 2100

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23

4

Fig. 7. Equation (2)–based forecast of changes in globaltemperature under different IPCC scenarios.(1) Data of instrumental measurements [7]; (2, 3, and 4)predicted values under scenarios A2, A1B, and B1, respec�tively.

1

2

3

1

2

3



crossed in 2050; under the B1 scenario, in 2060.According to the equation (2)–based forecast, underthe first two scenarios, temperature will cross thisboundary in 2070; under the B1 scenario, this will nothappen at all. This situation gives humankind moretime to solve the problem of anthropogenic green�house gas emissions.

ACKNOWLEDGMENTS

This work was supported by the Federal Target Pro�gram Scientific and Scientific–Educational HumanResources of Innovative Russia for 2009–2013 (agree�ment no. 8107).

REFERENCES

1. United Nations Framework Convention on ClimateChange (UN, 1992).

2. Climate Change 2007: Synthesis Report. Contribution ofWorking Groups I, II, and III to the Fourth AssessmentReport of the Intergovernmental Panel on ClimateChange, Ed. by R. K. Pachauri and A. Reisinger (IPCC,Geneva, 2007).

3. Managing the Risks of Extreme Events and Disasters toAdvance Climate Change Adaptation: IPCC SpecialReport, Ed. by C. B. Field, V. Barros, T. F. Stocker, et al.(Cambridge Univ. Press, Cambridge, 2012).

4. Z. M. Gudkovich, V. P. Karklin, V. M. Smolyanitskii,and I. E. Frolov, “What is happening to the Earth’s cli�mate?,” Ekol. Vestn. Ross., No. 5 (2012).

5. L. B. Klyashtorin, “Comparative dynamics of globalArctic climate: Predictability,” in Global EnvironmentalProcesses: Proceedings of the International ScientificConference (Academia, Moscow, 2012) [in Russian].

6. S.�I. Akasofu, Two Natural Components of the RecentClimate Change: (1) The Recovery from the Little IceAge (a Possible Cause of Global Warming) and (2) theMulti�Decadal Oscillation (the Recent Halting of theWarming) 2009. http://people.iarc.uaf.edu/~saka�sofu/pdf/Natural_Components_of_Climate_Change

7. P. D. Jones, D. E. Parker, T. J. Osborn, and K. R. Briffa,“Global and hemispheric temperature anomalies—land and marine instrumental records,” in Trends:A Compendium of Data on Global Change (CarbonDioxide Information Analysis Center, Oak RidgeNational Laboratory, U.S. Department of Energy, OakRidge, 2012). http://cdiac.ornl.gov/trends/temp/jone�scru/ jones.html. doi 10.3334/CDIAC/cli.002

8. L. R. Brown, Empty Plates: The New Geopolitics of FoodScarcity: Supporting Data (Earth Policy Institute, Wash�ington, 2012). http://www.earth�policy.org/books/fpep/fpep_data

9. P. Tans and R. Keeling, Trends in Atmospheric CarbonDioxide (Earth System Research Laboratory, GlobalMonitoring Division, NOAA, Boulder, 2012). http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.html

10. NOAA Paleoclimatology Reconstructions Network(NOAA, Boulder, 2012). http://www.ncdc.noaa.gov/paleo/pubs/pcn/pcn.html

11. T. A. Boden, G. Marland, and R. J. Andres, Global,Regional, and National Fossil�Fuel CO2 Emissions,(Carbon Dioxide Information Analysis Center, OakRidge National Laboratory, U.S. Department ofEnergy, Oak Ridge, 2012); doi 10.3334/CDIAC/00001_V2012; http://cdiac.ornl.gov/trends/emis/tre_glob.html

12. Carbon Dioxide: Projected Emissions and Concentrations(IPCC Data Distribution Center, 2011).http://www.ipcc�data.org/ddc_co2.html

13. D. Rind, J. Lean, J. Lerner, et al., “Exploring thestratospheric/tropospheric response to solar forcing,”J. Geophys. Res. 113, D24103 (2008). doi10.1029/2008JD010114

14. O. G. Sorokhtin, “The evolution of the Earth’s climateand the genesis of glacial epochs,” Her. Russ. Acad. Sci.76 (4), 332 (2006).

15. A. P. Ballantyne, C. B. Alden, J. B. Miller, et al.,“Increase in observed net carbon dioxide uptake byland and oceans during the past 50 years,” Nature 488,70 (2012). doi 10.1038/nature11299

16. R. N. Bates, “Multi�decadal uptake of carbon dioxideinto subtropical mode water of the North AtlanticOcean,” Biogeosci. 9, 2649 (2012). doi 10.5194/bg�9�2649�2012

17. A. S. Monin and Yu. A. Shishkov, “Climate as a prob�lem of physics,” Phys. Usp. 43, 381 (2000).

18. J. T. Kiehl and K. E. Trenberth, “Earth’s annual globalmean energy budget,” Bull. Am. Meteorol. Soc., No. 2(1997).

19. Z. M. Gudkovich, V. P. Karklin, V. M. Smolyanitskii,and I. E. Frolov, “Transition from the Earth’s climatewarming to cooling as a result of natural causes,” in Glo�bal Environmental Processes: Proceedings of the Interna�tional Scientific Conference (Academia, Moscow, 2012)[in Russian].

20. M. E. Mann, Z. Zhang, M. K. Hughes, R. S. Bradley,et al., “Proxy�based reconstructions of hemisphericand global surface temperature variations over the pasttwo millennia,” in Proceedings of the National Academyof Sciences 105, 13252 (2008). doi10.1073/pnas.0805721105

21. P. E. Damon and J. L. Jirikowic, “The Sun as a low�fre�quency harmonic oscillator,” Radiocarbon, No. 2(1992).

22. H. Braun, M. Christ, S. Rahmstorf, et al., “Possiblesolar origin of the 1,470�year glacial climate cycle dem�onstrated in a coupled model,” Nature 438, 208 (2005).doi 10.1038/nature04121

23. I. G. Usoskin, S. K. Solanki, and G. A. Kovaltsov,“Grand minima and maxima of solar activity: Newobservational constraints,” Astronomy and Astrophys.471, 301 (2007).

24. Emissions Scenarios: IPCC Special Report, Ed. byN. Nakicenovic and R. Swart (Cambridge Univ. Press,Cambridge, 2000).

Translated by B. Alekseev

the natural and anthropogenic concepts of contemporary climate warming

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