Working Group 2 of the international Panel on Climate Change is tasked with evaluating the impacts of climate change and how we might adapt to it. Their report, Climate Change 2014: Impacts, Adaptation, and Vulnerability came out today. Here’s some of the take-away, with links to more information.

“In recent decades, changes in climate have caused impacts on natural and human systems on all continents and across the oceans.”

Shepherd and sheep in Tibet: A key risk of climate change is the loss of rural livelihoods, especially in the least developed countries. The impacts of climate change will be felt most strongly by the poor and vulnerable in all nations.

Here are key risks to human and natural systems that the working group has a high confidence will occur, based on the state of our knowledge so far:

• food insecurity and the breakdown of food systems linked to warming, drought, flooding, and precipitation variability and extremes, particularly for poorer populations in urban and rural settings.

• loss of terrestrial and inland water ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for livelihoods.
• loss of marine and coastal ecosystems, biodiversity, and the ecosystem goods, functions, and services they provide for coastal livelihoods, especially for fishing communities in the tropics and the Arctic.
• death, injury, ill-health, or disrupted livelihoods in low-lying coastal zones and small island developing states and other small islands, due to storm surges, coastal flooding, and sea-level rise.
• severe ill-health and disrupted livelihoods for large urban populations due to inland flooding in some regions. risks due to extreme weather events leading to breakdown of infrastructure networks and critical services such as electricity, water supply, and health and emergency services.
• mortality and morbidity during periods of extreme heat, particularly for vulnerable urban populations and those working outdoors in urban or rural areas.
• loss of rural livelihoods and income due to insufficient access to drinking and irrigation water and reduced agricultural productivity, particularly for farmers and pastoralists with minimal capital in semi-arid regions.
• Many key risks constitute particular challenges for the least developed countries and vulnerable communities, given their limited ability to cope.

“Increasing magnitudes of warming increase the likelihood of severe, pervasive, and irreversible impacts. “

This is a sobering list. Loss of ecosystems. Increased food insecurity. Ill health. Disrupted livelihood.

This chart from the IPCC shows projected temperatures with little or no mitigation efforts (orange) and projected temperatures with mitigation efforts (blue).

Yet the effects will be even worse if we do nothing to mitigate climate change by lowering global greenhouse gas emissions and undertaking other mitigation efforts. The Climate Change 2014 report says that while some risks of climate change are considerable at 1 or 2°C above preindustrial levels, climate change risks become “ very high” with global mean temperature increase of 4°C or more.

These risks include “severe and widespread impacts on unique and threatened systems, substantial species extinction, large risks to global and regional food security, and the combination of high temperature and humidity compromising normal human activities. The precise levels of climate change sufficient to trigger tipping points (thresholds for abrupt and irreversible change) remain uncertain, but the risk associated with crossing multiple tipping in human and natural systems increases with rising temperature .”

“The overall risks of climate change impacts can be reduced by limiting the rate and magnitude of climate change. “

But all is not lost.

The Climate Change 2014 report says that risks are reduced substantially with lower temperature rise. Climate change impacts may be less likely to overwhelm human and natural systems and might be easier to adapt to. But the sooner mitigation efforts are undertaken, the less dire the consequences of climate change.

This is a challenge, when few national governments are making even close to the efforts that will be needed to avoid the worst effects of climate change. It is the task of everyone alive in the world today – and our governments – to make sure that the higher temperature rises do not occur. 

Here’s a link to a video about the Climate change 2014 report.
And here’s a link to a page where you can download the full Climate Change 2014 report or a summary for policymakers.

More on the IPCC

The Intergovernmental Panel on Climate Change (IPCC) was established by the United Nations Environment Program (UNEP) and the World Meteorological Organization (WMO) in 1988 to provide the world with a clear scientific view on the current state of knowledge in climate change and its potential environmental and socio-economic impacts.

The IPCC reviews and assesses the most recent scientific, technical and socioeconomic information produced worldwide relevant to the understanding of climate change. Thousands of sicentists from throughout contribute to the IPCC”s work (on a voluntary basis)
It is the role of the IPCC to inform governments about the most up-to-date scientific knowledge on an issue and, where appropriate, to highlight policy options to overcome challenges, but the IPCC never promotes one set of policy options over another.

The Assessment Report and the three working  groups

The decision to prepare a Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) with three Working Group contributions and a Synthesis Report was taken by the member governments of the IPCC at their 28th Session in April 2008.
Working Group II assesses impacts, adaptation, and vulnerability. Working Group I assesses the physical science basis of climate change, while Working Group III assesses the mitigation of climate change.. Working Group I deals with “The Physical Science Basis of Climate Change”, Working Group II with “Climate Change Impacts, Adaptation and Vulnerability” and Working Group III with “Mitigation of Climate Change”. A Synthesis Report will draw on the assessments made by all three Working Groups

What does Working Group 2 do?

The IPCC Working Group II (WG II) assesses the vulnerability of socio-economic and natural systems to climate change, negative and positive consequences of climate change, and options for adapting to it. It also takes into consideration the inter-relationship between vulnerability, adaptation and sustainable development. The assessed information is considered by sectors (water resources; ecosystems; food & forests; coastal systems; industry; human health) and regions (Africa; Asia; Australia & New Zealand; Europe; Latin America; North America; Polar Regions; Small Islands).

Wild Western climate

On March 13, the U.S. Drought Monitor said Carson City was in extreme drought, along with much of northwestern Nevada.

Ancestral Puebloan ruins, Cedar Mesa, Utah: photo Chas Macquarie

So I’ve been reading about drought in the American West, and I discovered the answer to some long-time mysteries. First, there are the tree stumps sticking out of the water in Tenaya Lake in Yosemite. The stumps sit about fifty yards off the beach in water so deep you can’t see the bottom. How did they get there?

The other mystery is the ancient adobe granaries perched on canyon walls in southern Utah. It was impossible not to notice, even for someone as unobservant as I was as a teenager, that the people who built their granaries way up the canyon walls must have been afraid of something.

Learning from paleoclimatology

Since my youth spent wandering around the various wilderness areas of the American west, the science of paleoclimatology has developed and those mysteries now have answers.
The trees now submerged by 70 feet of water grew there when Tenaya Lake dried up, probably around 800 years ago, in a period known as the medieval drought, or medieval climate anomaly. The medieval drought lasted 500 years (interrupted in the middle by a 100-year wet spell).

And the granaries? That same severe drought destroyed the civilization of the Ancestral Puebloan people of the southwest canyons. As the climate dried, desperate people hoarded their remaining food in spots as inaccessible as possible, to defend it from other desperate people.

Sacramento’s K street during great flood of 1861-62. Lithograph courtesy Wikipedia

Paleoclimatology tells us that the climate of the American West is one of regular drought and floods – including droughts lasting hundreds of years and floods big enough to turn California’s Central Valley into a lake, as happened in the great flood of 1861. The 150 years since European American settlement have been relatively benign climate-wise, but there is no assurance that will continue. And when mega droughts do come again, it will be to a region where millions of people now live.

Is this our future?

Human-caused climate change is expected to increase the frequency, intensity, and duration of droughts in the American west. In The West Without Water, B. Lynn Ingram writes, “The American West faces a climatic future that is predicted to become generally warmer and drier, with deeper droughts interspersed with larger and more frequent floods. The American West appears to be facing a potential climatic double-whammy: a cyclical return of drier conditions and new greenhouse-gas-induced warming.”

With this emerging understanding of our wild western climate, it is clear that we need to be planning for drought and conserving what water we have. Curious about how Carson City is doing in the current drought, I talked to Curtis Horton, Chief of Operations for Carson City’s water system, and David Bruketta, Carson City Utility Manager.

They told me about 95% of our water is from municipal wells and 5% is surface water.
How are those water supplies affected by the current drought? Curtis said right now we’re in good shape, though if the drought lasts another five years we could be hurting. The immediate effect of the drought is that we will lose our surface water earlier this year and will rely more on municipal wells. But the City has just completed a Regional Intertie project bringing water from the Minden area to Carson City. Components of the Intertie are operational but it will be a few more years before it is complete. This water will help us out in current and future droughts.

I asked if the City has done any long-range planning regarding maintaining adequate water supplies during multi-year droughts. The Regional Intertie, David said, is part of that long-range planning, and our water system, with the addition of the Regional Intertie, should support population growth to around 70,000 people.

Better off than Las Vegas – for now

Compare this to the predicament of Las Vegas, where the Water District is constructing a so-called “third straw” in Lake Mead – a third domestic water intake, at a cost of $800 million, for when the level of Lake Mead falls below the first two.

And still, some climate scientists estimate that with predicted reduction of runoff in the Colorado River Basin, “there’s a 50% chance that both Lake Mead and Lake Powell could reach ‘dead pool,’ rendering them useless for hydroelectric power generation or useful water storage by as early as 2021.”

In Carson City we’re much better off than that – for now.

(This post by blog editor Anne Macquarie was originally published in the Nevada Appeal under the title “Drought packs a heavy punch for the West” on Wednesday, March 19, 2014)