Status : this preprint was under review for the journal CP but the revision was not accepted.
Estimate of climate sensitivity from carbonate microfossils dated near the Eocene-Oligocene global cooling
M. W. Asten
M. W. Asten
M. W. Asten
School of Geosciences, Monash University, Melbourne, VIC 3800, Australia
Received: 09 Sep 2012 – Discussion started: 05 Oct 2012
Climate sensitivity is a crucial parameter in global temperature modelling. An estimate is made at the time 33.4 Ma using published high-resolution deep-sea temperature proxy obtained from foraminiferal δ18 O records from DSDP site 744, combined with published data for atmospheric partial pressure of CO2 (p CO2 ) from carbonate microfossils, where δ11 B provides a proxy for p CO2 . The p CO2 data shows a p CO2 decrease accompanying the major cooling event of about 4 °C from greenhouse conditions to icecap conditions following the Eocene-Oligocene boundary (33.7 My). During the cooling p CO2 fell from 1150 to 770 ppmv. The cooling event was followed by a rapid and huge increase in p CO2 back to 1130 ppmv in the space of 50 000 yr. The large p CO2 increase was accompanied by a small deep-ocean temperature increase estimated as 0.59 ± 0.063 °C. Climate sensitivity estimated from the latter is 1.1 ± 0.4 °C (66% confidence) compared with the IPCC central value of 3 °C. The post Eocene-Oligocene transition (33.4 Ma) value of 1.1 °C obtained here is lower than those published from Holocene and Pleistocene glaciation-related temperature data (800 Kya to present) but is of similar order to sensitivity estimates published from satellite observations of tropospheric and sea-surface temperature variations. The value of 1.1 °C is grossly different from estimates up to 9 °C published from paleo-temperature studies of Pliocene (3 to 4 Mya) age sediments. The range of apparent climate sensitivity values available from paleo-temperature data suggests that either feedback mechanisms vary widely for the different measurement conditions, or additional factors beyond currently used feedbacks are affecting global temperature-CO2 relationships.
M. W. Asten
Status: closed
Status: closed
AC : Author comment | RC : Referee comment | SC : Short comment | EC : Editor comment
- Printer-friendly version
- Supplement
Status: closed
Status: closed
AC : Author comment | RC : Referee comment | SC : Short comment | EC : Editor comment
- Printer-friendly version
- Supplement
M. W. Asten
Viewed
Total article views: 5,006 (including HTML, PDF, and XML)
HTML
PDF
XML
Total
BibTeX
EndNote
3,507
1,354
145
5,006
91
126
HTML: 3,507
PDF: 1,354
XML: 145
Total: 5,006
BibTeX: 91
EndNote: 126
Views and downloads (calculated since 01 Feb 2013)
Month
HTML
PDF
XML
Total
Feb 2013
90
88
4
182
Mar 2013
422
78
11
511
Apr 2013
77
51
2
130
May 2013
50
141
0
191
Jun 2013
33
53
0
86
Jul 2013
40
44
1
85
Aug 2013
36
16
1
53
Sep 2013
28
72
1
101
Oct 2013
25
24
0
49
Nov 2013
22
14
0
36
Dec 2013
42
20
0
62
Jan 2014
46
20
0
66
Feb 2014
249
19
2
270
Mar 2014
25
21
0
46
Apr 2014
48
15
0
63
May 2014
51
24
16
91
Jun 2014
23
16
0
39
Jul 2014
20
17
0
37
Aug 2014
30
12
0
42
Sep 2014
21
11
0
32
Oct 2014
27
17
1
45
Nov 2014
74
32
0
106
Dec 2014
12
47
0
59
Jan 2015
9
23
0
32
Feb 2015
18
7
2
27
Mar 2015
23
3
0
26
Apr 2015
17
16
0
33
May 2015
17
13
1
31
Jun 2015
28
17
0
45
Jul 2015
38
9
2
49
Aug 2015
25
9
0
34
Sep 2015
22
8
0
30
Oct 2015
27
11
2
40
Nov 2015
27
8
2
37
Dec 2015
21
13
4
38
Jan 2016
36
13
2
51
Feb 2016
38
10
1
49
Mar 2016
19
3
0
22
Apr 2016
16
8
0
24
May 2016
19
22
0
41
Jun 2016
16
2
0
18
Jul 2016
17
4
1
22
Aug 2016
16
7
1
24
Sep 2016
15
4
0
19
Oct 2016
14
2
0
16
Nov 2016
11
2
1
14
Dec 2016
4
4
0
8
Jan 2017
15
4
1
20
Feb 2017
24
1
3
28
Mar 2017
35
5
16
56
Apr 2017
60
5
11
76
May 2017
45
2
11
58
Jun 2017
48
4
8
60
Jul 2017
20
7
1
28
Aug 2017
16
3
0
19
Sep 2017
20
6
0
26
Oct 2017
88
2
0
90
Nov 2017
25
1
0
26
Dec 2017
16
2
0
18
Jan 2018
26
4
0
30
Feb 2018
21
1
3
25
Mar 2018
11
2
1
14
Apr 2018
25
5
0
30
May 2018
19
7
3
29
Jun 2018
16
3
0
19
Jul 2018
29
4
1
34
Aug 2018
17
3
0
20
Sep 2018
22
10
0
32
Oct 2018
26
4
0
30
Nov 2018
24
7
2
33
Dec 2018
15
4
0
19
Jan 2019
13
4
1
18
Feb 2019
10
0
10
Mar 2019
8
1
0
9
Apr 2019
11
7
1
19
May 2019
10
1
0
11
Jun 2019
3
23
0
26
Jul 2019
12
5
0
17
Aug 2019
13
3
0
16
Sep 2019
4
2
1
7
Oct 2019
10
4
1
15
Nov 2019
11
1
1
13
Dec 2019
11
2
0
13
Jan 2020
9
5
0
14
Feb 2020
14
1
1
16
Mar 2020
2
1
0
3
Apr 2020
8
3
0
11
May 2020
8
0
8
Jun 2020
12
4
0
16
Jul 2020
10
7
9
26
Aug 2020
4
2
3
9
Sep 2020
5
3
0
8
Oct 2020
11
3
1
15
Nov 2020
14
5
1
20
Dec 2020
14
6
1
21
Jan 2021
21
5
0
26
Feb 2021
20
3
0
23
Mar 2021
16
3
0
19
Apr 2021
26
6
2
34
May 2021
34
3
0
37
Jun 2021
20
1
0
21
Jul 2021
21
6
0
27
Aug 2021
17
4
0
21
Sep 2021
21
3
0
24
Oct 2021
25
6
0
31
Nov 2021
36
3
0
39
Dec 2021
27
3
0
30
Jan 2022
25
5
0
30
Feb 2022
26
3
0
29
Mar 2022
11
2
1
14
Apr 2022
24
1
0
25
May 2022
43
3
0
46
Jun 2022
13
4
0
17
Jul 2022
40
2
0
42
Aug 2022
46
8
0
54
Sep 2022
40
6
0
46
Oct 2022
38
3
1
42
Nov 2022
14
3
0
17
Dec 2022
23
5
1
29
Jan 2023
6
4
0
10
Cumulative views and downloads
(calculated since 01 Feb 2013)
Month
HTML views
PDF downloads
XML downloads
Feb 2013
90
88
4
Mar 2013
512
166
15
Apr 2013
589
217
17
May 2013
639
358
17
Jun 2013
672
411
17
Jul 2013
712
455
18
Aug 2013
748
471
19
Sep 2013
776
543
20
Oct 2013
801
567
20
Nov 2013
823
581
20
Dec 2013
865
601
20
Jan 2014
911
621
20
Feb 2014
1,160
640
22
Mar 2014
1,185
661
22
Apr 2014
1,233
676
22
May 2014
1,284
700
38
Jun 2014
1,307
716
38
Jul 2014
1,327
733
38
Aug 2014
1,357
745
38
Sep 2014
1,378
756
38
Oct 2014
1,405
773
39
Nov 2014
1,479
805
39
Dec 2014
1,491
852
39
Jan 2015
1,500
875
39
Feb 2015
1,518
882
41
Mar 2015
1,541
885
41
Apr 2015
1,558
901
41
May 2015
1,575
914
42
Jun 2015
1,603
931
42
Jul 2015
1,641
940
44
Aug 2015
1,666
949
44
Sep 2015
1,688
957
44
Oct 2015
1,715
968
46
Nov 2015
1,742
976
48
Dec 2015
1,763
989
52
Jan 2016
1,799
1,002
54
Feb 2016
1,837
1,012
55
Mar 2016
1,856
1,015
55
Apr 2016
1,872
1,023
55
May 2016
1,891
1,045
55
Jun 2016
1,907
1,047
55
Jul 2016
1,924
1,051
56
Aug 2016
1,940
1,058
57
Sep 2016
1,955
1,062
57
Oct 2016
1,969
1,064
57
Nov 2016
1,980
1,066
58
Dec 2016
1,984
1,070
58
Jan 2017
1,999
1,074
59
Feb 2017
2,023
1,075
62
Mar 2017
2,058
1,080
78
Apr 2017
2,118
1,085
89
May 2017
2,163
1,087
100
Jun 2017
2,211
1,091
108
Jul 2017
2,231
1,098
109
Aug 2017
2,247
1,101
109
Sep 2017
2,267
1,107
109
Oct 2017
2,355
1,109
109
Nov 2017
2,380
1,110
109
Dec 2017
2,396
1,112
109
Jan 2018
2,422
1,116
109
Feb 2018
2,443
1,117
112
Mar 2018
2,454
1,119
113
Apr 2018
2,479
1,124
113
May 2018
2,498
1,131
116
Jun 2018
2,514
1,134
116
Jul 2018
2,543
1,138
117
Aug 2018
2,560
1,141
117
Sep 2018
2,582
1,151
117
Oct 2018
2,608
1,155
117
Nov 2018
2,632
1,162
119
Dec 2018
2,647
1,166
119
Jan 2019
2,660
1,170
120
Feb 2019
2,670
1,170
120
Mar 2019
2,678
1,171
120
Apr 2019
2,689
1,178
121
May 2019
2,699
1,179
121
Jun 2019
2,702
1,202
121
Jul 2019
2,714
1,207
121
Aug 2019
2,727
1,210
121
Sep 2019
2,731
1,212
122
Oct 2019
2,741
1,216
123
Nov 2019
2,752
1,217
124
Dec 2019
2,763
1,219
124
Jan 2020
2,772
1,224
124
Feb 2020
2,786
1,225
125
Mar 2020
2,788
1,226
125
Apr 2020
2,796
1,229
125
May 2020
2,804
1,229
125
Jun 2020
2,816
1,233
125
Jul 2020
2,826
1,240
134
Aug 2020
2,830
1,242
137
Sep 2020
2,835
1,245
137
Oct 2020
2,846
1,248
138
Nov 2020
2,860
1,253
139
Dec 2020
2,874
1,259
140
Jan 2021
2,895
1,264
140
Feb 2021
2,915
1,267
140
Mar 2021
2,931
1,270
140
Apr 2021
2,957
1,276
142
May 2021
2,991
1,279
142
Jun 2021
3,011
1,280
142
Jul 2021
3,032
1,286
142
Aug 2021
3,049
1,290
142
Sep 2021
3,070
1,293
142
Oct 2021
3,095
1,299
142
Nov 2021
3,131
1,302
142
Dec 2021
3,158
1,305
142
Jan 2022
3,183
1,310
142
Feb 2022
3,209
1,313
142
Mar 2022
3,220
1,315
143
Apr 2022
3,244
1,316
143
May 2022
3,287
1,319
143
Jun 2022
3,300
1,323
143
Jul 2022
3,340
1,325
143
Aug 2022
3,386
1,333
143
Sep 2022
3,426
1,339
143
Oct 2022
3,464
1,342
144
Nov 2022
3,478
1,345
144
Dec 2022
3,501
1,350
145
Jan 2023
3,507
1,354
145
Saved
Latest update: 28 Jan 2023