A recent paper in Science is worth noting for its ominous implications: future warming is predicted on the “high side”:
BOULDER—Climate model projections showing a greater rise in global temperature are likely to prove more accurate than those showing a lesser rise, according to a new analysis by scientists at the National Center for Atmospheric Research (NCAR). The findings, published in this week’s issue of Science, could provide a breakthrough in the longstanding quest to narrow the range of global warming expected in coming decades and beyond.
An observable constraint on climate sensitivity, based on variations in mid-tropospheric relative humidity (RH) and their impact on clouds, is proposed. We show that the tropics and subtropics are linked by teleconnections that induce seasonal RH variations that relate strongly to albedo (via clouds), and that this covariability is mimicked in a warming climate. A present-day analog for future trends is thus identified whereby the intensity of subtropical dry zones in models associated with the boreal monsoon is strongly linked to projected cloud trends, reflected solar radiation, and model sensitivity. Many models, particularly those with low climate sensitivity, fail to adequately resolve these teleconnections and hence are identifiably biased. Improving model fidelity in matching observed variations provides a viable path forward for better predicting future climate.
Climate change is likely to be more severe than some models have implied, according to a study which ratchets up the possible temperature rises and subsequent climatic impacts. Climate model projections showing a greater rise in global temperature were likely to be more accurate than those showing a smaller rise, an analysis by the US National Centre for Atmospheric Research found. This means not only a higher level of warming, but also that the resulting problems – including floods, droughts, sea level rise and fiercer storms and other extreme weather – would be correspondingly more severe and would come sooner than expected.
Scientists at the centre published their study last Thursday in the leading peer-reviewed journal Science. It is based on an analysis of how well computer models estimating the future climate reproduce the humidity in the tropics and subtropics that has been observed in recent years. They found that the most accurate models were most likely to best reproduce cloud cover, which is a major influence on warming. These models were also those that showed the highest global temperature rises in the future if emissions of greenhouse gases continue to increase.
Rather than leave you the impression that “We’re doomed! Doomed!” I do believe it is vital we discuss the implications of this paper (and the voluminous other evidence) and begin examining how our civilisation can remain viable in the anthropocene.
Personally, I believe it is possible: but we need to look at the world in a new way. We live on what is essentially a different planet - very different to the one our species and civilisation witnessed as they came into being.
Even at this stage we have choices: to scale back greenhouse emissions; to implement renewable sources of energy; to better manage resource use; and to curb our growth fetish.