I was stunned when I looked at NASA’s plot of monthly temperature anomalies showing that not only was July the hottest July ever recorded, it was the hottest month ever recorded, and the most recent (maybe not the last!) in an streak of new monthly records going back 10 months.
There is shock value in seeing the whitespace on this graph separating the recent sequence of consecutive anomalies from the 136 years previous period of record.
There is now ample physical evidence that the science of climate change may have got it right.
There was always the possibility that climate dynamics are more complex in reality than what we account for with our simplistic modeling assumptions. With greater complexity comes greater resilience. There are bound to be many atmosphere/hydrosphere/lithosphere/biosphere/cryosphere interactions that we don’t understand and that we will only be able to discover with the benefit of hindsight. While some of those dynamics could accelerate change, some must impart stability. Perhaps we have been focusing on the ‘bad’ dynamics and not looking hard enough for the ‘good’ dynamics.
This plot of monthly anomalies is not what you would expect to see from a resilient system.
What does this mean for water resources? You could do a calculation to find out. The Clausius-Clapeyron relation relates vapor pressure to temperature, which could be used to estimate the increase in water holding capacity of the entire atmosphere due to this change in temperature. I haven’t done that but would speculate that the increase in temperature is enough to swell the size of some atmospheric rivers to an Amazonian scale. It also means that in water supply limited landscapes every last drop of water will be sucked up to satisfy this water vapor deficit.
Does this mean that dry places will get dryer and wet places will get wetter? Maybe, but maybe not.
The high Arctic is warming disproportionately to the rest of the world. Arctic sea ice is disappearing and the ice-free season is getting longer. The jet stream is sensitive to the temperature differential between the tropics and the Arctic and hence, can’t be counted on to continue to deliver weather following historic patterns. Some dry places may get wetter and some wet places may get dryer.
If you are in California or Africa you may welcome a new atmospheric river hosing down an abundance of fresh water. But too much of a good thing can be a bad thing. Wet landscapes, such as the Amazon have had millennia to develop sufficient conveyance capacity for their water abundance. In contrast, dry landscapes are maladapted to handle massive volumes of water.
I like to be optimistic about our future. After all, if we found a nearby planet that was identical to earth in every respect except it was two degrees warmer we would be building massive rocket ships to get as many people there as quickly as possible.
We can adapt. I just wasn’t expecting that we would need to adapt quite as quickly as this graph indicates.
July 2015 was the hottest month in recorded history according to NOAA! Extreme droughts around the world are creating an opportunity for hydrologists to record a historic event. Every drop counts. Every measurement counts. Droughts are a global problem that require new hydrological insight. Stu Hamilton’s latest whitepaper presents 7 best practices for monitoring water during droughts. Read whitepaper here.