Atmospheric and Climate Sciences, 2017, 7, 256-262
http://www.scirp.org/journal/acs
ISSN Online: 2160-0422
ISSN Print: 2160-0414
DOI: 10.4236/acs.2017.73018
July 4, 2017
On the Possible Contribution of Natural
Climatic Fluctuations to the Global
Warming of the Last 135 Years
Maxim Ogurtsov
1,2
, Markus Lindholm
3
, Risto Jalkanen
3
1
Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg, Russia
2
General Astronomical observatory at Pulkovo, St. Petersburg, Russia
3
Natural Resources Institute Finland (Luke), Rovaniemi, Finland
Abstract
A number of numerical experiments with artificial random signals (the
second order autoregressive processes), which have important statistical pro
perties similar to that of the observed instrumental temperature (1850-
2015),
were carried out. The results show that in frame of the selected mathematical
model the return period of cl
imatic events, analogous to the current global
warming (linear increase of temperature for 0.95˚C
during the last 135 years)
is 2849-5180 years (one event per 2849-
5180 years). This means that global
warming (GW) of the last 135 years can unlikely be fully explained by inh
e-
rent oscillations of the climatic system. It was found however, that natural
fluctuations of climate may appreciably contribute to the GW. The return p
riod of climatic episodes with 0.5˚C
warming during the 135 years (half of the
observed GW) was less than 500 years. The result testifies that the role of e
x-
ternal factors (emission of greenhouse gases, solar activity etc.) in the GW
could be less than often presumed.
Keywords
Global Warming, Climate, Natural Oscillations
1. Introduction
It is generally well-known that the mean surface temperature of the globe has
been rising during more than last century [1] [2]. It is widely accepted also that
this GW is caused primarily by anthropogenic increase of greenhouse gases
concentration [1] [2]. However debates on this question still continue. Some ex-
perts maintain that current warming does not exceed the natural fluctuations of
Ogurtsov, M.,
, M. and Jalkanen, R. (2017)
On
the Possible Contribution of Natural Cl
i-
s to the Global
Warming
of the Last 135 Years
.
Atmospheric and
Climate Sciences
,
, 256-262.
http://dx.doi.org/10.4236/acs.2017.73018
March 31, 2017
July 1, 2017
July 4, 2017
7 by authors and
Research Publishing Inc.
This work is licensed under the Creative
International
4.0).
http://creativecommons.org/licenses/by/4.0/