High temperatures exacerbated by #climatechange made 2022 Northern Hemisphere droughts more likely: “The models analysed also show that soil moisture #drought will continue to increase with additional #globalwarming” — World Weather Attribution #ActOnClimate

Yampa River at Phippsburg June 14, 2022. Photo credit: Scott Hummer

Click the link to read the release on the World Weather Attribution website:

Western Central Europe, North America, China, and other parts of the Northern Hemisphere faced water shortages, extreme heat, and soil moisture drought conditions throughout the summer of 2022

Water shortages, extensive fires, high food prices and severe crop losses were among the most important impacts of one of the hottest European summers on record, with heat waves and exceptionally low rainfall across the Northern Hemisphere. These conditions led to very dry soils particularly in France, Germany and other central European countries (called West-Central Europe in the following); mainland China also experienced exceptionally high temperatures and dryness. These deficits in soil moisture led to poor harvests in the affected regions, increased fire risk, and, in combination with already very high food prices, is expected to threaten food security across the world.

Scientists from Switzerland, India, the Netherlands, France, the United States of America and the United Kingdom, collaborated to assess to what extent human-induced climate change altered the likelihood and intensity of the low soil moisture, both at the surface and the root zones for most crops.

Figure 1: a) Anomaly in the June to August average root zone soil moisture w.r.t 1950-2022 climate over the northern hemisphere so-called ‘extratropics’ (NHET) region (full domain shown) based on the ERA5-Land dataset. The smaller region West-Central Europe (WCE) is highlighted by the red box. (b) same as (a) for surface soil moisture.

Main findings

– Heat and low rainfall in West-Central Europe had far reaching impacts on a variety of sectors including human health, energy, agriculture, and municipal water supply. It was exacerbated by e.g. poor water infrastructure and leakages, and it came at a time when food and energy prices were already high resulting in compounding social and economic impacts.

– In this study, we particularly focus on the dry soils which caused severe economic and ecological impacts across the Northern Hemisphere (excluding the tropical regions) and were particularly severe in West-Central Europe. We therefore focus on these two regions, North-Hemisphere extratropics and West-Central Europe, to analyse the agricultural and ecological drought from June to August 2022.

– Observation-driven land surface models show that very low summer surface and root-zone soil moisture, such as observed in 2022, happens about once in 20 years in today’s climate in both regions.

– While the magnitude of historical trends vary between different observation-based soil moisture products, all agree that the dry conditions observed in 2022 over both regions would have been less likely to occur at the beginning of the 20th century.

– To determine the role of climate change in these observed changes, we combine the observation-based datasets with climate models and conclude that human-induced climate change increased the likelihood of the observed soil moisture drought events. The change in likelihood is larger in the observation-based data compared to the models.

– We also assessed the role of climate change in temperature and rainfall in these regions and found that the strong increase in high temperatures is the main reason for the increased drought.

– Combining all lines of evidence we find for West-Central Europe that human-induced climate change made the 2022 root zone soil moisture drought about 3-4 times more likely,  and the surface soil moisture drought about 5-6 times more likely.

– For the Northern Hemisphere extratropics, human-induced climate change made the observed soil moisture drought much more likely, by a factor of at least 20 for the root zone soil moisture and at least 5 for the surface soil moisture, but as is usually the case with hard to observe quantities, the exact numbers are uncertain.

– The models analysed also show that soil moisture drought will continue to increase with additional global warming, which is consistent with projected long-term trends in climate models as reported e.g., in the IPCC AR6.

#California is going to take 9% less #water from the #ColoradoRiver — National Public Radio #COriver #aridification

Southern California water agencies have agreed on a deal to cut back on the amount of water they use for the Colorado River, some of which is used to grow crops in the Imperial Valley. Ted Wood/The Water Desk

Click the link to read the article on the National Public Radio website (Juana Summers/Alex Hager). Here’s an excerpt:

SUMMERS: Thanks for being here. So this summer, the federal government told the states that share the Colorado River that they needed to write plans to take significantly less water due to the decade-long drought. California has now been the first to respond. How do they plan to meet this goal?

HAGER: Yeah, Southern California is proposing to cut back by about 9%. And they’re still sorting out the details of who exactly will give up how much water, but this is a deal that’s bringing together suppliers for farms and cities alike. So the four agencies involved kind of have the ability to spread out the impact of those cuts. And this announcement comes amid mounting pressure for them to use less. The federal government asked the states that share the river to conserve. And, you know, a lot of those states responded by pointing fingers at California, which uses by far the most water from the river. So now this is California’s response. They’re coming out with the first major water conservation deal since the feds asked for cuts.

SUMMERS: OK. But what are they asking for in return?

HAGER: The California group is asking for federal money to help with the Salton Sea. It’s this big, salty lake that gets filled with irrigation runoff from nearby farms. But when there’s less water heading to California, that lake dries up. And then all the salt and dust that’s left behind – it’s causing an ecological and health crisis for the area.

Brad Udall: Here’s the latest version of my 4-Panel plot thru Water Year (Oct-Sep) of 2021 of the Colorado River big reservoirs, natural flows, precipitation, and temperature. Data (PRISM) goes back or 1906 (or 1935 for reservoirs.) This updates previous work with @GreatLakesPeck. Credit: Brad Udall via Twitter

Click the link to read “More water restrictions likely as California pledges to cut use of Colorado River supply” on The Los Angeles Times website (Ian James). Here’s an excerpt:

With the Colorado River in crisis and reservoir levels continuing to decline, some California water agencies are planning to significantly reduce the amount they take from the river starting next year. As a result, officials with the Metropolitan Water District of Southern California said they plan to endorse mandatory conservation measures to begin rationing water for cities and local agencies that supply 19 million people across six counties…Four water districts and the state’s Colorado River Board said in a letter to the federal government on Wednesday that they are proposing to reduce water use by up to 400,000 acre-feet per year. That would amount to about 9% of the state’s total water allotment from the river for the next four years, through 2026…

The All American Canal carries water from the Colorado River to farms in California’s Imperial Valley. The Imperial Irrigation District holds more rights to Colorado River water than any other user in the basin. Photo credit: Adam Dubrowa, FEMA/Wikipedia.

“California is stepping up and leading the way on addressing this situation with action and making significant reductions,” said J.B. Hamby, a board member of the Imperial Irrigation District…

Hamby said the reductions “are going to involve serious sacrifice within California, but it’s necessary in order to prevent the system from crashing.”

California water agencies have been under pressure to shoulder substantial water cutbacks. Federal officials in June called for the seven states that rely on the Colorado River to come up with plans to drastically reduce annual water diversions by 2 million to 4 million acre-feet. But negotiations among the states grew tense and acrimonious, and didn’t produce a deal.

The @CWCB_DNR “Confluence Newsletter October 2022” is hot off the presses

Click the link to read the news letter on the Colorado Water Conservation Board website. Here’s an excerpt:

Federal Technical Assistance Grants for Colorado Water Projects

As part of the American Rescue Plan Act, a total of $5 million in federal funding has been allocated for technical assistance grants that will enable eligible entities to work with the Colorado Water Conservation Board (CWCB) contractors or to hire contractors to expand their capacity and expertise, in pursuit of federal funding opportunities that directly support the Colorado Water Plan objectives. The allowable uses of this grant funding are broad in scope, to allow for the wide range of federal opportunities available. Funding can be used for: preliminary project planning and design, preliminary permitting, development of estimated project costs, navigation of available federal opportunities, grant writing, and federal grant application submittal. A minimum of 25% matching funds is required. Grants will be awarded on a rolling basis through December 2024; grant funds must be fully expended by December 2026.

There are two categories of technical assistance for federal grants:

  1. Local Capacity Grants: There is $2.5 million total available for technical assistance for local water projects in which local grantees hire their own contractor(s) to assist with the application process. This funding is currently available.
  2. CWCB Technical Assistance: The remaining $2.5 million is available for technical assistance for local water projects in which the Colorado Water Conservation Board (CWCB) provides selected contractors to support the application process. NOTE: This option for technical assistance is not yet available. Information will be provided on this webpage as it becomes available.

For a list of potential federal grant opportunities, visit the Water Funding Opportunity Navigator.

Clean Heat Plan Emissions Calculation Guidance and Calculation Workbook — #Colorado #AirPollution Control Division #ActOnClimate

From email from the Colorado AirPollution Control Division:

The Air Pollution Control Division has published the Clean Heat Plan Emissions Calculation Guidance and CHP Calculation Workbook. The published documents can be found HERE. The Division has created these documents through a technical stakeholder process to develop a consistent approach to evaluating the emissions reduction projections from Clean Heat Plans required by Senate Bill 21-264.

Background: To address climate change and meet requirements from Senate Bill 21-264, the Air Pollution Control Division has consulted with the Public Utilities Commission related to the calculation methodology for evaluating clean heat plans for gas utilities. Starting in 2023, gas utilities are required to submit clean heat plans to the Public Utilities Commission or the Division to verify that they are designed to meet greenhouse gas reduction targets.

The Four Corners methane hotspot is yet another environmental climate and public health disaster served to our community by industry. But now that we’ve identified the sources we can begin to hold those responsible accountable for cleaning up after themselves. The BLM methane rule and EPA methane rule are more clearly essential than ever. Photo credit: San Juan Citizens Alliance (2018)

Navajo Dam operations update (October 8, 2022): Bumping releases down to 450 cfs #SanJuanRiver #ColoradoRiver #aridification

From email from Reclamation (Susan Novak Behery):

In response to wet weather and sufficient flows in the critical habitat reach, the Bureau of Reclamation has scheduled a decrease in the release from Navajo Dam from 550 cubic feet per second (cfs) to 450 cfs for tomorrow, October 8th, at 4:00 AM.

Releases are made for the authorized purposes of the Navajo Unit, and to attempt to maintain a target base flow through the endangered fish critical habitat reach of the San Juan River (Farmington to Lake Powell).  The San Juan River Basin Recovery Implementation Program recommends a target base flow of between 500 cfs and 1,000 cfs through the critical habitat area.  The target base flow is calculated as the weekly average of gaged flows throughout the critical habitat area from Farmington to Lake Powell.

The San Juan Generating Station in mid-June of 2022 The two middle units (#2 and #3) were shut down in 2017 to help the plant comply with air pollution limits. Unit #1 shut down mid-June 2022 and #4 was shut down on September 30, 2022. Jonathan P. Thompson photo.