foofighter
Jedi Council Member
After having read Laura's article on the cyclic climate changes I did some Googling on the topic and found this interesting paper, published in 2004:
"Merging information from different resources for new insights into climate change in the past and future"
http://www.geo.lsa.umich.edu/~shaopeng/2004GL019781.pdf
From the abstract:
"An understanding of climate history prior to
industrialization is crucial to understanding the nature of
the 20th century warming and to predicting the climate
change in the near future. This study integrates the
complementary information preserved in the global
database of borehole temperatures [Huang et al., 2000],
the 20th century meteorological record [Jones et al., 1999],
and an annually resolved multi proxy model [Mann et
al., 1999] for a more complete picture of the Northern
Hemisphere temperature change over the past five centuries.
The integrated reconstruction shows that the 20th century
warming is a continuation to a long-term warming started
before the onset of industrialization. However, the warming
appears to have been accelerated towards the present day."
It's an interesting read, and in particular Figure 4 Right shows clearly the relationship between surface temperatures and what he calls "radiative forcing", which includes solar irradiance,
anthropogenic aerosols, and greenhouse gases. There's also diagrams where volcanism is included in the radiative forcing, but the correlation between temperature and radiative forcing then diminishes quite a lot.
Since greenhouse gases are included in the radiative forcing it could be argued that they are an important part of the climate changes, but as Huang points out these changes started before the industrialization period. Even if some part of it is indeed caused by humanity, it would have happened anyway.
"Merging information from different resources for new insights into climate change in the past and future"
http://www.geo.lsa.umich.edu/~shaopeng/2004GL019781.pdf
From the abstract:
"An understanding of climate history prior to
industrialization is crucial to understanding the nature of
the 20th century warming and to predicting the climate
change in the near future. This study integrates the
complementary information preserved in the global
database of borehole temperatures [Huang et al., 2000],
the 20th century meteorological record [Jones et al., 1999],
and an annually resolved multi proxy model [Mann et
al., 1999] for a more complete picture of the Northern
Hemisphere temperature change over the past five centuries.
The integrated reconstruction shows that the 20th century
warming is a continuation to a long-term warming started
before the onset of industrialization. However, the warming
appears to have been accelerated towards the present day."
It's an interesting read, and in particular Figure 4 Right shows clearly the relationship between surface temperatures and what he calls "radiative forcing", which includes solar irradiance,
anthropogenic aerosols, and greenhouse gases. There's also diagrams where volcanism is included in the radiative forcing, but the correlation between temperature and radiative forcing then diminishes quite a lot.
Since greenhouse gases are included in the radiative forcing it could be argued that they are an important part of the climate changes, but as Huang points out these changes started before the industrialization period. Even if some part of it is indeed caused by humanity, it would have happened anyway.