MMario,

paid subscription? You mean you can't see it? Well, I can and I don't pay, but perhaps access is paid by my university and I didn't know.

Here's the summary of the first link:

New Take on Climate Modeling

The world is getting hotter, and humans are at least partly to blame--but that's about all that climate researchers can confidently say about global warming. Their bottom-up approach--trying to understand the role of every part in the dizzyingly complex climate machine--has left the crucial question of how bad things could get unanswered. In the 4 January issue of Science, a group of researchers describe a new top-down approach: They plugged different combinations of values for fundamental properties of the climate system into a computer model and looked to see how well the model's output matched long-term observations. The results suggest that global warming is probably a serious threat and that it could get even hotter than most scientists believe.

As Mark has pointed out, both seemingly conflicting articles could even be true (or one or none) if global warming would lead to more precipitation in Antarctica. That could mean, for instance that global warming could come with many of the foretold bad consequences like more deserts and storms and all that, but without the predicted amount of sea level rise.

Some early models you have read of just simply (which doesn't mean that they are simple to work out; simple models are difficult enough) assume that temperature rises, eveything else is constant, and then calculate sea level rise. But then you can start thinking
- that a higher temperature leads to more evaporation on the oceans and therefore more precipitation in the Antarctica, but wait
- can't warmer air hold more water without raining, but perhaps
- with warmer weather there'll be more plant growth which effectively storages water,
- but what will that do to the CO 2 level in the atmosphere...?

The main reason for disagreement is that tiny variations in the assumptions or starting values of those models still lead to grossly different conclusions.

From a local point of view, global warming even could make the climate colder. Some of the models predict the gulf stream to stop transporting warm water from the Carribbean to Europe. That would lead to half of Scandinavia being covered with ice and to a breakdown of European economy due to local cooling.

Wolfgang