Strong negative feedback in any system leads to linear dependence of system's output on its input. (scienceofdoom.com)
In this particular environment, it doesn't look like there are strong negative feedbacks on erosion rates because the material appears to be simply too fine - grained and ice - rich to be redeposited locally and form barriers, bars, etc.. (dotearth.blogs.nytimes.com)
Expectation of small but positive CO2 - greenhouse warming is consistent with his claims of strong negative feedbacks by upper tropospheric water vapor or cirrus clouds which would lose sense without initial warming in the global tropics. (julesandjames.blogspot.ru)