What are the psychological impacts of climate change?

Increased fre­quency and intens­ity of nat­ur­al dis­asters, extreme weath­er events, dam­age to biod­iversity and eco­sys­tems… The phys­ic­al effects of cli­mate change are now being felt in every coun­try in the world. In its 2022 report “Impacts, Adapt­a­tion and Vul­ner­ab­il­ity”, the IPCC high­lighted for the first time anoth­er import­ant aspect of cli­mate change: its adverse effect on the well-being and men­tal health of pop­u­la­tions. The cli­mate emer­gency is also a men­tal health emer­gency. For every per­son phys­ic­ally affected by a cli­mate dis­aster, 40 are affected psy­cho­lo­gic­ally, says the report from the Grantham Insti­tute at Imper­i­al Col­lege Lon­don, UK. But what are the prac­tic­al psy­cho­lo­gic­al effects of cli­mate change? 

In recent years, there has been a lot of talk about eco-anxi­ety as a way of refer­ring to the neg­at­ive emo­tions gen­er­ated by the cli­mate situ­ation. Susan Clayton, Chair of Psy­cho­logy at the Uni­ver­sity of Woost­er in the United States, is one of the authors of the IPCC report. This spe­cial­ist in the rela­tion­ship between humans and nature points out that “eco-anxi­ety is not in itself a sign of men­tal ill­ness; it is a nor­mal response to a very wor­ry­ing situ­ation. How­ever, some people reach a level of anxi­ety that threatens their men­tal health. This can affect their sleep, their abil­ity to con­cen­trate and work, or to relax and have fun.” 

The psy­cho­lo­gist stud­ied eco-anxi­ety to determ­ine wheth­er this phe­nomen­on had real implic­a­tions for men­tal health, or wheth­er it was just a word for cli­mate “woes”. With her col­league Bry­an T. Karaz­sia, Susan Clayton developed a scale based on men­tal health meas­ures. The aim was to check wheth­er meas­ures of eco-anxi­ety were cor­rel­ated with estab­lished meas­ures of psy­cho­lo­gic­al prob­lems. And this was indeed the case: eco-anxi­ety can there­fore, in some cases, have a sig­ni­fic­ant psy­cho­lo­gic­al impact. 

Anoth­er emo­tion is also cited in the report from the Grantham Insti­tute at Imper­i­al Col­lege Lon­don, sol­asta­gia. “It is a feel­ing of home­sick­ness for a place in which you are actu­ally liv­ing. It’s see­ing changes in your ter­rit­ory, and hav­ing a sense of grief, of loss as a res­ult,” says Jes­sica New­berry Le Vay, a fel­low at the Insti­tute for Glob­al Health Innov­a­tion at Imper­i­al Col­lege Lon­don. The pop­u­la­tions most affected are chil­dren, people work­ing on the land, and indi­gen­ous com­munit­ies, who wit­ness first-hand the changes in the land­scape around them. 

The report states that there is a 1% increase in sui­cide rates for every 1°C increase in temperature.

Cli­mate change involves slow and gradu­al changes in our envir­on­ments. One of these is rising tem­per­at­ures. In addi­tion to its impact on the eco­sys­tem, this phe­nomen­on has ser­i­ous con­sequences for men­tal health. High tem­per­at­ures are asso­ci­ated with high­er rates of sui­cide, but also of psy­chi­at­ric hos­pit­al­isa­tion. “There is an approx­im­ate 1% increase in sui­cide rates for every 1°C increase in tem­per­at­ure above a spe­cif­ic threshold for each geo­graph­ic­al area,” says Jes­sica New­berry Le Vay. People who suf­fer from men­tal ill­ness, par­tic­u­larly psy­chos­is, demen­tia, or addic­tion, are two to three times more likely to die dur­ing heat­waves than people without men­tal health prob­lems, the Grantham Insti­tute report says. In addi­tion, there is also an increase in con­flict, viol­ence – espe­cially domest­ic viol­ence – and assaults. “The gen­er­al level of well-being is fall­ing,” says Susan Clayton.

While we don’t yet know exactly why heat has these effects, there are some pos­sible explan­a­tions. High tem­per­at­ures dis­rupt sleep, which is an essen­tial com­pon­ent of men­tal health. Tem­per­at­ure changes can also cre­ate physiolo­gic­al changes, affect­ing blood flow and the nervous sys­tem, which will have cog­nit­ive and emo­tion­al impacts, the Grantham Insti­tute argues. 

Cli­mate change affects pop­u­la­tions indir­ectly, through aware­ness of its effects, through the con­sequences on ter­rit­or­ies, through the threat to food, eco­nom­ic or hous­ing secur­ity. “These are stress factors that can lead to psy­cho­lo­gic­al prob­lems,” says psy­cho­lo­gist Susan Clayton. Cli­mate change also dam­ages people’s phys­ic­al and men­tal health dir­ectly, through extreme weath­er events, which are observed in all regions of the world. Fires, hur­ricanes, and floods are on the rise, and the IPCC expects these events to increase as warm­ing pro­gresses. Many research­ers have looked at the psy­cho­lo­gic­al effects of these dis­asters. Susan Clayton reviewed this lit­er­at­ure for the IPCC report. The most com­mon symp­toms are post-trau­mat­ic stress, anxi­ety, depres­sion, increased stress, feel­ings of grief, bereave­ment, and uncer­tainty about the future. 

As of 2019, the term cli­mate trauma refers to the psy­cho­lo­gic­al dis­tress caused by envir­on­ment­al destruc­tion. Jyoti Mishra, a pro­fess­or of psy­chi­atry at the Uni­ver­sity of Cali­for­nia San Diego, spe­cial­ising in neur­os­cience and men­tal health, is work­ing on the dead­li­est fire in California’s his­tory, the Camp Fire. Occur­ring from 8^th-26^th Novem­ber 2018, the fire rav­aged 620 km² of forest, and des­troyed the town of Para­dise. Its first study quan­ti­fied the num­ber of people who repor­ted trauma. The num­ber of symp­toms such as post-trau­mat­ic stress, depres­sion or anxi­ety was two to three times high­er in people who had exper­i­enced the fire, com­pared to those who had not been exposed to it.

In Janu­ary this year, Jyoti Mishra pub­lished the first study to exam­ine the neur­o­lo­gic­al and cog­nit­ive impacts of weath­er-related trauma. The aim is to determ­ine wheth­er brain func­tion is affected by expos­ure to an extreme weath­er event. 75 people took part in the study six to twelve months after the fire. Of these, 27 were dir­ectly exposed to the fire either through the destruc­tion of their home or the loss of a loved one; 21 were indir­ectly exposed as they wit­nessed the fire but were not per­son­ally affected; and 27 were not exposed at all. 

Cog­nit­ive tests were developed to ana­lyse the men­tal pro­cesses involved in memory, learn­ing, think­ing and inter­fer­ence pro­cessing, i.e. the abil­ity to ignore dis­trac­tions. “For an hour, indi­vidu­als were giv­en these tests to focus their atten­tion on some­thing, to make their memory work. All brain activ­ity was recor­ded with an elec­tro­en­ceph­al­o­gram,” the psy­chi­at­rist explains. “These tests were chosen because they are at the heart of human cog­nit­ive abil­it­ies, and they have been shown to be import­ant abil­it­ies in the con­text of trauma, depres­sion or men­tal health problems.”

To observe inter­fer­ence pro­cessing, par­ti­cipants were asked to focus on an object in the middle of a screen, such as a fish, and say wheth­er it was point­ing left or right. Mean­while, oth­er objects appeared on the screen. Those exposed to the fires, both dir­ectly and indir­ectly, had 20% less accur­ate responses than the con­trol group. This meant that they were more dis­trac­ted and had more dif­fi­culty con­cen­trat­ing on a task.

People exposed to fire have more dif­fi­culty con­cen­trat­ing on a task.

“In addi­tion, we found great­er front­al and pari­et­al brain activ­ity for the dir­ectly exposed group. This means that the brain is mak­ing more effort to func­tion, to stay focused and attent­ive,” says the study author. “This can be com­pared to the exper­i­ence of people suf­fer­ing from post-trau­mat­ic stress dis­order, who become very aware and attent­ive to their envir­on­ment, and pay atten­tion to everything because everything seems like a threat.”

For Jyoti Mishra, it is very import­ant to devel­op sim­il­ar research to under­stand the effects of cli­mate trauma on our brain, on our bio­logy. These res­ults can help nor­m­al­ise these symp­toms and devel­op more appro­pri­ate treat­ments. But are these cli­mate-related psy­cho­lo­gic­al exper­i­ences spe­cif­ic to oth­er prob­lems already iden­ti­fied, such as post-trau­mat­ic stress dis­order? “We don’t know at the moment. It seems that there are dif­fer­ences in the symp­toms, but also in the best way to treat them thera­peut­ic­ally. We are still in the early stages, and we need more research,” says Susan Clayton. 

What has been widely doc­u­mented by research is that we are not all equal when it comes to cli­mate change-related men­tal health prob­lems. People who are already vul­ner­able in soci­ety are even more likely to devel­op prob­lems. “This is because of the resources avail­able to cope with these events, includ­ing prac­tic­al resources such as air con­di­tion­ing, shel­ter, and eco­nom­ic and social resources,” says the Amer­ic­an psy­cho­lo­gist. Some groups are more affected, such as the eco­nom­ic­ally dis­ad­vant­aged, chil­dren, the eld­erly and women. 

So, what can be done to mit­ig­ate these psy­cho­lo­gic­al impacts? In addi­tion to devel­op­ing research on these sub­jects, to refine treat­ments, spe­cial­ists agree on the need to increase the resources alloc­ated to men­tal health. “We need to provide people with emo­tion­al tools and cre­ate sup­port and assist­ance net­works for people who have exper­i­enced dis­asters,” say Susan Clayton and Jes­sica New­berry Le Vay. It is also pos­sible to act upstream to avoid these impacts, by devel­op­ing easi­er access to nature and safe hous­ing, and by strength­en­ing safe social ties.

Sirine Azouaoui