Arctic ice seems to be trending downward, and fluctuation more rapidly.<p><a href="http://images.dailytech.com/nimage/9972_large_daily.gsia.jpg" rel="nofollow">http://images.dailytech.com/nimage/9972_large_daily.gsia.jpg</a><p>But that's rather immaterial since it's land based ice, as in greenland and antarctica, that will influence sea levels. Greater fluctuations will cause more permanent loss of land based ice than sea based ice.<p>But <i>that's</i> rather immaterial too, since much of the expected and currently visible sea level rise comes from thermal expansion of the oceans. This is a pretty clear temperature link.<p>---<p>Perhaps the most relevant limits of which I speak are regarding the extent to which we are willing to change our world. This is a separate question from the action of CO2 -- for example we already fix more nitrogen as all other life on this planet, and three quarters of the land based biomes on this planet have been dramatically influenced by our actions. <i>We have changed this planet.</i> Are we to become conscious of this or are we to continue claiming innocence and practicing ignorance as we accelerate our ecological impact?<p>A return to the atmospheric conditions of the Triassic might well be the best thing for the world, but as long as people continued to be confused, lazy and stupid about what kind of future we want, we will continue to argue about tiny details having little to nothing to do with the global atmospheric, ecological, biological climatic change that is taking place, and we will continue to be at odds as our actions annihilate biomes that we scarcely know about.<p>I put the question back to you. What change in the world would be acceptable to you? If we have reconcilable goals for our shared planet, then at least the debate becomes on of science, of planning, of what must be done. If, however, like many seem to think, you too believe that the changes we are making to the world are ultimately inconsequential, the loss of biodiversity acceptable, and our gambling with the ecosystem immaterial, then we are at odds that this conversation will not mend.