Right off the bat, I do want to affirm that there is a very real sense in which hell is now, is here. I don't mean to deny the idea that what happened in Japan, what happened in Haiti, what happens in abusive homes and crackhouses and in genocidal tribalism is in a real sense hell on earth. But I think the emphasis on this concept of hell -- rather than the concept of hell as a "place" of punitive wrath after death for those not found in Christ -- is problematic for a couple of very significant reasons.
1. The concept of "hell on earth now" is largely foreign to the New Testament. We may find it between the lines, implied, of course. And the Bible does talk a lot in various ways about creation's diverse groanings and systemic injustice, etc. But the primary way the Scriptures refer to hell is as a place of post-mortem punishment.
2. The concept of "hell on earth now" (in the form of systemic brokenness, the sufferings of happenstance, etc.) removes the primary reason for hell: punishment via condemnation due to personally offending God. The emphasis on hell now to the marginalization of hell later diminishes the overarching justification for hell, which is sin against God. Hell in the form of tsunamis and economic inequality positions us as victims, not rebels. And "victims" is not the way the New Testament primarily refers to us.