Is there any world-wide ranking of conferences/journals? I know it's rather difficult to establish a ranking of publications, especially because the ones in charge of establishing values for venues might be biased by their field, and several other aspects. However, I know some well-accepted (at least locally) ranking, that consider all fields under research, e.g. Brazilian Qualis - in portuguese - that includes both confs and journals, and Australian ERA - this latter has served as baseline for some class A conferences in Computer Science (my research field), in some countries other than Australia. 

Hence, I wonder about the existence of another "global ranking", that has been applied overseas, thus including at least the most prominent events and journals in every field. For journals, it's a little bit easier to measure its importance, by looking at their Impact Factor values, but for conferences it's a little bit tough. To the best of my knowledge, I don't know a largely-applied means of measuring the impact of a conf.

I'd like to hear from you. Thanks in advance.
In Computer Science, CiteSeerX used to provide a Venue Impact Factor, that included journals and conferences, but it seems they've stopped doing it. As indicated by Gopi, Microsoft academic Research is some kind of global ranking, and JeffE also mentions google.scholar.

That being said, a global ranking, across sub-fields, is not necessarily meaningful. For instance, if one does not work on programming languages, then it's unlikely to submit a paper at POPL (the first venue according to CiteseerX). Hence, I'd say that field-specific rankings matter more, for instance in security: http://faculty.cs.tamu.edu/guofei/sec_conf_stat.htm or https://personal.cis.strath.ac.uk/changyu.dong/ranking.html.