Climate risk Assessment: Lawrence, Massachusetts

Panoramic photo of North Canal in Lawrence, MA. / photo by Terageorge~commonswiki (CC BY-NC-ND 4.0)

Introduction

The impacts of climate change on the frequency and severity of physical hazards are putting many communities at risk. As the threat of climate change grows, so too does the need for accessible information, tools, and expertise to support climate-resilient decision making for municipalities. Woodwell Climate Research Center (“Woodwell”) believes there is a need to localize and customize climate risk assessments. This information is critical for local government leaders as they make planning decisions, but it is not available to all communities. Woodwell believes that this science should be freely and widely available. To address this gap, Woodwell works with communities across the world, including Lawrence, MA, to provide municipal climate assessments, free of charge.

Results summary

As a result of climate change, temperatures are projected to increase in Lawrence, Massachusetts. The probability of the 100-year rainfall event, a useful indicator of flood risk, will likely triple by the mid 21st century and more than quadruple by the end of the century. In addition to periods of extreme rainfall, the city can expect the frequency of drought to increase. Negative impacts associated with these climate hazards will be disproportionately felt by elderly, poor, and minority populations. Groundwork Lawrence (groundworklawrence.org) has been actively engaged with the community in efforts to address these imbalances. Here we present our findings on extreme precipitation, flooding, drought, and heat to help Lawrence in its plans to create a more resilient future for all residents.

Extreme precipitation and flooding

The trend of intensification of extreme precipitation in the Northeast US is expected to continue under future warming. Intensification here speaks to both more frequency and more severe rainfall events. Here we use localized future precipitation data from a regional climate model1 to calculate the change in probability of extreme rainfall events. In Figures 1 and 2 we show the changes in the return period of the historical (2000–2020) 100-year rainfall event for 2040–2060 and 2070–2090, respectively. By 2040–2060, the historical 100-year event will occur with a return period between 1-in-20 and 1-in-50 in the Merrimack River valley and approximately 1-in-30 in Lawrence, MA. By 2070–2090, the 100-year event will become a 1-in-15 year event for the region.

According to the National Atlas 14 published by the National Oceanic and Atmospheric Administration, the 100-year rainfall amount in Lawrence, MA is 7.85 inches. By 2040-2060, the 100-year amount increases to 10.97 inches and by 2070-2090 this further rises to 13.3 inches. The increase in rainfall translates to larger streamflows and increased flood extents as shown in Figure 3. The historical floodplain2, based on 20th and early 21st century rainfall and streamflow data, covers large portions of downtown Lawrence, especially on the southern bank of the Merrimack river because the location is the point of confluence with the Shawsheen river. The commercial and municipal district, including the courthouse and Lawrence General Hospital on the north bank of the Merrimack river, are also susceptible to flood impacts due to the convergence of the Spicket and Merrimack rivers at the eastern edge of the Lawrence city limits. The historical floodplain impacts 1,952 structures within the Lawrence city limits. By 2040–2060, the number of structures increases to 2,688 and by 2070-2090 the figure further increases to 3,093. The stormwater system was not included in the flood modeling effort because data was not available from the City of Lawrence; however, it is highly likely that the efficacy of the stormwater system would be compromised during periods of extreme water levels on the Merrimack, Spicket, and Shawsheen rivers as outfalls may be temporarily submerged. Additionally, according to the City of Lawrence Stormwater Management Program Plan3 dated June 2021, there is no stormwater infrastructure located in southern Lawrence between MA-28 and Andover Street which becomes heavily inundated during the 100-year rainfall event.

Can farmers fight climate change? New U.S. law gives them billions to try

Cutting emissions from fertilizer and livestock will be key, scientists say

Tanguro Ranch, Brazil 2018

When settlers plowed the North American prairie, they uncovered some of the most fertile soil in the world. But tilling those deep-rooted grasslands released massive amounts of underground carbon into the atmosphere. More greenhouse gases wafted into the skies when wetlands were drained and forests cleared for fields. Land conversion continues today, and synthetic fertilizer, diesel-hungry farm machinery, and methane-belching livestock add to the climate effects; all told, farming generates 10% of climate-affecting emissions from the United States each year. Now, Congress would like to turn back the clock and return some of that carbon to the soil.

Read more on Science Insider.

Woodwell Climate Research Center has worked for years to understand and highlight the scale of the global climate crisis and has called upon policymakers to act with urgency in addressing this threat. The Inflation Reduction Act (IRA) is historically significant legislation, providing incentives and policy tools to dramatically reduce U.S. greenhouse gas emissions and put the United States within reach of its nationally determined contribution (NDC) for climate action.

A robust analysis by Princeton University’s ZERO Lab estimates the impact of IRA projects on greenhouse gas emissions to be a reduction to 40 percent below 2005 levels, by 2030. The U.S. NDC sets a target of 50 percent reduction below 2005 levels. With additional action from the private sector and state and local governments, the United States has a realistic chance to meet its current climate targets and set a path toward a safe and stable climate.

Of course, this legislation is not perfect. In particular, there are fossil fuel provisions in the bill that seem antithetical to climate action. But the net result of this legislation is overwhelmingly positive for the climate, and is the most substantial step forward for climate policy in U.S. history.

Numerous sections of the bill touch on areas of specific Woodwell expertise. Natural climate solutions are essential for meeting both U.S. and global emissions targets, and Woodwell scientists have focused much of their research on the most effective strategies to maximize carbon storage in forests and soils. The IRA invests heavily in natural climate solutions.

FORESTRY

The Inflation Reduction Act addresses the fact that climate change can accelerate wildfires, and also the importance of trees and forests for carbon sequestration and climate change mitigation. Among other forestry provisions:

AGRICULTURE

The Inflation Reduction Act provides significant incentives for improved agricultural techniques that would, among other benefits, increase soil carbon sequestration. Existing federal agricultural conservation programs, for example, are heavily oversubscribed, and the Act provides additional funds to help farmers and ranchers implement and expand practices that would reduce greenhouse gas emissions. Woodwell scientists have been among the leaders in researching the potential of soil carbon as a climate change mitigation tool, and the processes for measuring, monitoring, and validating increased sequestration. Among other conservation and agricultural provisions, the Act includes:

RISK

The Inflation Reduction Act recognizes the current and increasing physical hazards presented by climate change, and the fact that many communities are not prepared for climate change impacts. Woodwell works with local governments around the world to provide granular climate services, free of charge. There remains, however, an enormous need to expand this science and to provide funding to support adaptation measures.

As Boston heat records fall, scientists see climate change’s fingerprints

Point to a string of 90-plus-degree days in Boston and call it climate change, and someone might tell you: There have always been hot days.

And it’s true. The historical records are full of occasional blips when temperatures soared.

But the relentless heat of this summer — the heavy curtain that has hung over Boston, making the air thick and the going slow — is different, and has been made more likely to happen thanks to climate change, according to scientists. And while these seemingly endless strings of scorching temperatures feel terrible, these experts say they are just a taste of what’s to come.

Continue reading on The Boston Globe.

Jet stream stokes both deadly Midwest flooding and Northwest heat

Deadly floods are slamming the US Heartland. More than 2,000 miles away, dangerous heat is scorching the Pacific Northwest. The same phenomenon is to blame for both.

A massive bend in the jet stream — narrow bands of high winds encircling the Earth — is causing the havoc. In the Northwest, the jet steam has curved far north, allowing hot air to surge into Oregon and Washington. In the Midwest and Appalachia, it’s dipped south, bringing cool from Canada that’s colliding with with tropical air from the Gulf of Mexico, triggering ruinous downpours in Missouri and Kentucky.

Read more on BNN Bloomberg.

Climate risk Assessment: Summit County, Utah

Summit County, Utah

Background

The impacts of climate change on the frequency and severity of physical hazards are putting many communities at risk. As the threat of climate change grows, so too does the need for accessible information, tools, and expertise to support climate-resilient decision making for municipalities. Woodwell Climate Research Center (“Woodwell”) believes there is a need to localize and customize climate risk assessments. This information is critical for local government leaders as they make planning decisions, but it is not available to all communities. Woodwell believes that the science should be freely and widely available. To address this gap, Woodwell works with communities across the world, including Summit County, UT, to provide municipal climate assessments, free of charge.

Introduction

As a result of climate change, drought is expected to become more frequent and extreme in Summit County, UT. Coupled with population growth, more extreme droughts will increase water scarcity in the region. These dry conditions will also lengthen the wildfire season. Factors such as income, profession, and proximity to wildlands will affect residents’ capacity for resilience during drought and wildfire events. Here we present our findings on severe drought, water scarcity, and wildfire danger days paired with wildland-urban interface and income data to help Summit County create a more resilient future.

Drought

The frequency of severe drought is expected to increase in the future for Summit County. Drought stress is based on the Palmer Drought Severity Index (PDSI), a metric used by the U.S. Drought Monitor. In the past two decades (2000–2020), central Summit County experienced severe, or worse, drought ≤ 20% of the time (Fig. 1a). By mid-century (2040–2060) and late-century (2071–2090), severe drought stress will increase to ≤ 30% of the time for this region (Fig. 1b and c).

In 2000–2020, the northern and easternmost regions of Summit County experienced severe drought conditions around 40% of the time. These conditions are expected to increase to around 50% of the time by mid- to late-century.

Park City1 experienced severe drought conditions ≤ 20% of the time in 2000–2020, and this is expected to increase to around 36% of the time by mid-century and 41% by late-century.

Water Scarcity

Whether used for drinking water, agriculture, or recreation, water underpins the health and economy of Summit County. Unfortunately, residents have already faced the hardships associated with water scarcity. Residents who rely on well water have experienced lower water quality as wells dry due to drought. In October 2021, a prolonged drought brought Echo Reservoir and Rockport Reservoir down to 11% and 26% of their total capacity. Towns responded by taking dramatic action in order to meet residents’ water needs. For example, Echo had water shipped in via fire truck. Both Oakley and Hennifer halted new construction that connected to city water. Farmers and ranchers have had to make hard decisions on how to irrigate crops and feed livestock. Small operators are especially at risk. As the climate changes, water will continue to be a crucial resource to preserve and protect.

We utilize a Water Scarcity Index (WSI) to determine the level of water scarcity in Summit County. The WSI is a relative global percentile ranking system based on ten hydrological variables using historical observations and future model projections.2 The Index indicates that 43,017 people living in Summit County face high water scarcity. This is equivalent to 97% of the county’s population. We use gridded 2020 population data from WorldPop3 to determine the population at risk. In the west where most of the county’s population resides in the major cities of Coalville, Park City, Oakley, and Kamas, the WSI score is in the 80th percentile compared to all other locations in the world, which we consider as high water scarcity (Fig. 2, left).

One factor driving high water scarcity is groundwater risk in the east. In the WSI, groundwater risk is measured by the time when groundwater pumping starts to impact environmental streamflow, a point known as the environmental flow limit, due to unsustainable rates of groundwater abstraction and low levels of groundwater recharge. Negative impacts of reaching the environmental flow limit include discharge from groundwater to streams to decline, reverse in direction, or stop altogether. In rural regions, groundwater is the primary and often only water source. As surface water resources become more strained, the reliance on groundwater will likely increase but will be limited by availability and quality. In the far eastern region of Summit County, the environmental flow limit was already reached as early as 2012 (Fig. 2, center). Roughly 5% of the population, or 2,136 people, live in an area where the limit was already exceeded. In the central Summit County and the Snyderville Basin, the environmental flow limit is not expected to be reached in this century. Park City may have additional exposure as they import water from the Jordanelle Reservoir, which surpassed its environmental flow limit in 1982.

The second main driving factor is high projected water stress throughout the county. Water stress is defined as the ratio of water withdrawals to available renewable water. In 2030 (midpoint of 2021–2040), the major cities in Summit County are projected to have a water stress ratio of 189% (Fig. 2, right). That means water demand is expected to be almost twice as much as available water supply. For reference, a high water stress ratio is considered to be 40%.4 The 2030 projected water stress in Coalville, Park City, Oakley, and Kamas is nearly 5x that amount. In the southern area of the Weber River watershed, the water stress level is projected to be as high as 250%. Generally, across the county, water stress increases 1.4x compared to 1986–2005 levels. High projected water stress in Summit County is driven by an increase in water demand as well as a decrease in water supply.

Wildfire

To assess future change in wildfire danger for Summit County, we analyzed Fire Weather Index (FWI) data.  FWI is a daily, unitless measurement of wildfire danger, derived from temperature, relative humidity, wind speed, and precipitation. This metric was developed by the Canadian Forest Service and is used globally, including in the United States, to quantify fire risk.

The change in wildfire danger days (Fig. 3) was calculated by determining the additional number of days per year in the future that are predicted to have a FWI value greater than the historical (2000–2020) extreme (1-in-20-day occurrence) FWI value. This threshold indicates a high-danger wildfire day, where fires have the potential to quickly grow out of control in the event of natural or human-caused ignition. By mid-century (2040–2060), much of Summit County can expect up to an additional six wildfire danger days per year (Fig. 3a). By late-century (2070–2090), central Summit County could experience up to an additional eight wildfire danger days per year compared to 2000–2020 (Fig. 3b). Easternmost and northwestern regions can expect an annual average additional 11 wildfire danger days by late-century, signifying a yearly increase of 60%.

Like many communities, Summit County has limited funds and resources available for wildfire prevention and suppression. The county can better prepare for the future by focusing on regions where wildfires have the greatest potential to cause damage to life and property. Figure 4 overlays human footprint data7 (indicating populated areas, housing, roads, etc) with biomass8 (trees and other vegetation) from 2018 to identify wildland-urban interfaces—potential hotspots for costly wildfires. The western side of Park City stands out as a region with a high human footprint and large amount of burnable vegetation. This area is also projected to see an increase in wildfire danger days (Fig. 3) and should be a main focus for wildfire mitigation. Building up defensible space around properties on the edge of town and conducting low-intensity prescribed burns that clear underbrush are two actions that can help reduce wildfire risk and severity for the city and surrounding areas and cultivate a healthy, diverse forest.

Past wildfire boundaries9 within Summit County from 1980–2019 are presented in Figure 5. The human footprint layer is once again overlaid to show where these historical fires occurred relative to human development. The county has experienced multiple wildfires along I-80 in the past three decades, including the 2013 Rockport Fire that burned over 2,000 acres near Atkinson and just a few miles northeast of Park City.

Not all residents of Summit County will be impacted equally in the event of a wildfire. Those with limited income will be disproportionately affected, as they often lack the resources to clear areas around their homes and recover economically in the event of a fire. The percent of individuals living below the 200% Federal Poverty Level (FPL)10 in Summit County are displayed in Figure 6 to highlight census blocks with vulnerable individuals. More than 25% of the population in northwestern Summit County is below the 200% FPL, and multiple wildfires have occurred in this census block in recent decades. Multiple census blocks in populous southwestern Summit County, including parts of Park City, have between 20–25% of individuals below the 200% FPL. Allocating resources to help limited-income residents develop and maintain defensible spaces around their homes is one preventative measure Summit County can take to aid in the reduction of wildfire risk in vulnerable communities. Provision of additional support for limited-income individuals after a wildfire event is also crucial in helping disproportionately impacted residents in their recovery.

 

Explainer: What’s causing the recent U.S. heat waves?

Much of the United States will experience another heat wave this week, with above-normal temperatures forecast for the Pacific Northwest, Southern Plains and the Lower Mississippi Valley.

The extreme heat is fueling a fast-moving California wildfire, just went of Yosemite National Park. The Oak Fire has destroyed 10 structures and is 10% contained.

The U.S. heat wave followed record heat that killed hundreds if not thousands of people and sparked wildfires in Europe.

Continue reading on Reuters.