Is there a global warming signal in hemispheric temperature series?
Global and hemispheric temperatures, greenhouse gas concentrations, solar irradiance, and anthropogenic sulfate aerosols all have increased during the last one hundred and fifty years. Classical linear regression techniques will indicate a positive relationship among such series whether or not such a relation exists. Such standard techniques cannot, therefore, show whether observed temperature increases are the result of anthropogenic climate change. However, recent developments in econometrics allow for the analysis of relationships between statistically non-stationary data. We apply some of these recently developed tests in order to uncover the presence of stochastic trends in global climate change variables. These tests indicate that the greenhouse gases are characterized by I(2) stochastic trends while they fail to find evidence of an I(2) stochastic trend in hemispheric temperature series. This would mean that there is no simple long-run equilibrium relationship between radiative forcing and temperature. We then use a multivariate structural time series model to decompose Northern and Southern Hemisphere temperatures into stochastic trends and autoregressive noise processes. This method does not suffer from some of the disadvantages of the standard tests. The results show that there are two independent stochastic trends. The first is I(2) and is shared by the Northern and Southern Hemisphere temperatures. It may be related to the to the radiative forcing variables and represent a global warming signal. The second trend is I(1) and is only present in Northern Hemisphere temperatures. This trend seems closely related to the radiative forcing due to tropospheric sulfates.
|Date of creation:||Nov 1997|
|Contact details of provider:|| Web page: http://incres.anu.edu.au/EEP/wp.html|
When requesting a correction, please mention this item's handle: RePEc:anu:wpieep:9708. See general information about how to correct material in RePEc.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: (Jack Pezzey)
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If references are entirely missing, you can add them using this form.
If the full references list an item that is present in RePEc, but the system did not link to it, you can help with this form.
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your profile, as there may be some citations waiting for confirmation.
Please note that corrections may take a couple of weeks to filter through the various RePEc services.