Ever wonder why so many Norwegians ended up in Minnesota? Or Azoreans in Central California? Or Vietnamese in Louisiana? Our new working paper introduces “climate matching” as a driver of migration.
Introducing the concept of climate matching as a driver of migration: movers select destinations with climates similar to their place of origin, from Marguerite Obolensky, Marco Tabellini, and
@ctaylor463
Given the buzz around Brood X, I’ll share some things I learned while writing my JMP. Cicadas are extraordinary critters…and a good natural experiment. I use them to estimate the impact of pesticides on infant mortality and educational outcomes.
This aligns with folk wisdom: “Newcomers from Europe commonly sought climatic conditions [in the US] like those in which they had been raised” - Calvin Coolidge.
(my grandfather’s favorite joke was that Norwegians chose Minnesota for its mild winters)
We find that migrants systematically seek out destinations with familiar climates. In other words, relative climate change is important to people, not just absolute climate.
And a bonus for those who love soils (only alluded to in the paper), we also find that farmer-migrants seek out familiar soils, minimizing the “soil distance” from their homeland soils in terms of soil bulk density, organic matter, pH, etc.
The relationship also holds within countries too: using linked Census data, we show that people from colder parts of Norway settled in colder parts of the US. Same holds for Germans (who remain the largest ancestry group in the US with 45 million).
Global agricultural land area has decreased in recent years. Natural lands are recovering. Why? Here's a long view on global land use and its economic drivers...since the 1800s w/
@jrising
- via
@IOPscience
Crop yields in the US have increased dramatically since the 1940s, driven by input usage, mechanization, irrigation, and crop genetics. But at the same, CO2 levels have increased, another driver of plant growth. Such co-trending effects are difficult to untangle.
CO2 data from NASA’s OCO-2 satellite finds a consistently high CO2 fertilization effect on US agriculture, explaining 10 to 40 percent of the observed yield trends since 1940, from
@ctaylor463
and Wolfram Schlenker
Tree planting is widely popular w/ programs from the Sahel to South Korea – but can it lead to *local* climate change?
@florian_grosset
@ctaylor463
and I study this in a new WP "Rain follows the forest: Land use policy, climate change, and adaptation" 1/8
And these patterns changed over time along with climate change: migration increased more between locations whose climate converged between 1900 and 2019!
We also explore the effects of climate “mismatch” in terms of mortality, and we estimate the value that people put on climate similarity using the Homestead Act of 1862 as a natural experiment.
Supreme Court just announced it will take on
#WOTUS
, determining which waters/wetlands are protected under the Clean Water Act. This is among the most important land use regulations in the US--with huge environmental and economic implications
@EPA
(1/2)
While climate was a bigger driver of migration in the past (more farmers; pre-AC), it remains a major factor today. As for drivers, we investigate the role of climate-specific skills (i.e., farming knowledge, construction methods) versus amenities/cultural preferences.
Working paper on wetlands and flooding with Hannah Druckenmiller
@rff
. We find higher damages in places downstream from wetland loss, including 'isolated' wetlands. In light of Hurricane Ida devastation, this highlights importance of wetlands as
@EPA
and
@USACEHQ
review
@wotus
Harvard Kennedy School is on the junior market this year for a position in macro, development, environmental and energy economics. Candidates should be able to teach macro at the graduate level. Interested candidates apply!!
Great to see this paper out. It tells us which lands are (likely) federally regulated, and which are not, under the Clean Water Act--a major source of uncertainty for decades! I bet it will prove useful to regulators, environmentalists, and developers alike.
New in
@ScienceMagazine
(my first research article there!): Machine learning predicts which rivers, wetlands the Clean Water Act regulates
Motivation: EPA and Army Corps say "EXISTING TOOLS CANNOT ACCURATELY MAP THE SCOPE OF CLEAN WATER ACT JURISDICTION"
Cicadas are harmless to humans. If you have trees in your yard, don’t worry. Damage is limited and mostly to young trees. If worried, you can put some mesh netting over them (rather than insecticide).
Thanks
@hagertynw
. The recent Sackett v. EPA ruling strips protection from wetlands lacking a continuous surface water connection to navigable waters--but these very wetlands are the "sponges" that protect our cities from flooding!
Too bad SCOTUS missed
@ctaylor463
and
@HannahDruck
's 2022 paper in the AER
"We evaluate wetland location relative to the surface water network and find that the most valuable wetlands for flood mitigation are those located 500 to 750 meters from the nearest stream or river."
Cicadas don’t harm agricultural crops like corn or soy (or humans, for that matter)—just trees. I use this as an additional source variation. A sharp increase in insecticide use coincides with cicada emergence only in places with high tree crop production.
@lukestein
Not quite QJE...but at least my JMP. Cicadas are wonderful, strange creatures. And the perfect natural experiment. I use them to assess the impact of pesticides on infant mortality and educational outcomes.
@leah_boustan
Congrats to ARE 2021 Alumna Hannah Druckenmiller on her American Economic Review publication out today: "Wetlands, Flooding, and the Clean Water Act" with Charles Taylor
@ctaylor463
@NatureAtCal
Thanks
@JonathanColmer
. I'm excited for the cicadas. They are truly wonderful creatures, harmless to people and agricultural crops. But they can damage orchards, a fact I use to assess long-term impacts of insecticides on health/development.
@JoshuaSGoodman
@hagertynw
@JoshuaSGoodman
They emerge in 13 and 17-year cycles. Charles Taylor (a grad student at Columbia has a nice paper, exploiting this variation. He finds higher insecticide use during gestation is associated with corresponding effects on infant health and test scores
Legal debates center on challenges to estimating the costs/benefits of wetland regulation. Our forthcoming paper provides an approach to estimating the value of wetlands for flood mitigation using detailed spatial data, including "isolated" wetlands (2/2)
Given this only happens once every 17 years, some more fun facts about cicadas.
1. Periodical cicadas only exist in the eastern half of the US…nowhere else in the world
2. Largest one-time source of biomass (weight in bugs per acre) of any creature on earth
Cicadas damage trees by laying eggs in branches. When the eggs hatch, nymphs fall to the ground and feed on roots (reducing tree growth). Tree farmers/orchards owners use insecticides to control this.
CALL FOR PAPERS, Climate Economics Pipeline Workshop, Harvard Kennedy School June 20, 2023. Workshop will feature research on climate change & climate change policy by doctoral students. Submit papers by April 15 at:
@RobertStavins
@HarvardWCFIA
@AereOrg
We reiterate that climate change will have a large negative impact on agriculture in aggregate, especially in places exposed to extreme heat. And higher CO2 may even lower food nutrition. But the countervailing fertilization effect should also be taken into account.
Important OpEd on the potentially very strong El Niño that's brewing in the Pacific. By
@AmirJina
@GCMcCord
@jesseXjesse
alums of
@SipaSusdev
El Niños Are Predictable. We Should Prepare for Their Possibly Disastrous Consequences.
7. Great song, but I think Self Portrait is actually a better album than New Morning 😬
8. Since there are no cicadas in NYC, I’ll be a
@cicadatourist
heading to the DC-area to see Brood X!
5. Brood X (current one) is the biggest. Brood VII is the tiniest, just in the Finger Lakes of NY (last in 2018)
6. Bob Dylan wrote “Day of the Locusts” after the getting an honorary degree from Princeton during the Brood X in 1970 (the great grandparents’ of today’s cicadas).
Other waters that stand to lose WOTUS protection are the intermittent streams common throughout the Western US--which, as seen in California this winter, are critical to mitigating flood waters.
@leah_boustan
Fun fact about Princeton cicadas: Bob Dylan wrote “Day of the Locusts” after the getting an honorary degree during the Brood X emergence in 1970. I guess they'd be this cohort's great-grandparents?
In this working paper with Wolfram Schlenker
@ColumbiaSIPA
, we use NASA's new OCO-2 satellite to estimate the CO2 fertilization effect on corn, soy, and wheat across the US. We find relatively large effects compared to FACE experiments.
3. Theory is that cicadas emerge in prime number intervals (13 and 17 years) for predator satiation reasons. Birds won’t be able to sync up and eat them all!
4. Chickens go on a feeding frenzy and lay more eggs (purely anecdotal…but how I came up with the research idea).
We find that the presence of a livestock plant in a county is associated with >50% more COVID-19 cases and >37% more deaths in July, after controlling for density, demographics, connectivity, etc. This holds for cattle, hog and poultry operations. 2/5
@linusblomqvist
@jrising
(likely captured in FAO’s harvested vs standing categorization)—a historical pattern seen in China, Europe, N America. Interesting that Potapov et al. find much of recent cropland growth in Africa, where many country GDPs are under the $5,000 transition threshold we find.