All you need to do is ask to be added to the group. Follow the directions here:

http://cmip-pcmdi.llnl.gov/cmip5/data_getting_started.html

thanks dear

Dear Muhammad

You know All ESGF data nodes down until the week of September 21th. So you can use other sites that ESGF refers them in its site. In following I write to you some of them. But first of all you should register on these sites and make sure that you have user and password, after that you can easily start download your desirable model. Be consider and careful to select spatial and temporal resolution of your aim model and after that start to download related data.

https://www.earthsystemgrid.org/

http://www.ipcc-data.org/sim/gcm_monthly/AR5/Reference-Archive.html .

http://www.ceda.ac.uk/services/archive-data-access/

http://data1.gfdl.noaa.gov/.

and many other sites....

Best Regards,

Nasrin

thank you