It seems that every year about this time, a few of my friends who are close to finishing graduate school email me asking how they can find out about academic jobs in the environmental social sciences. Since I have one of those coveted positions, I may have some expertise in the area. Unfortunately, the answer is a little complex. Most disciplines have standardized repositories for posting academic jobs - often sorted by key categories. For example, the American Political Science Association has a job board in which jobs are listed under the major divisions of political science - i.e. comparative, American, international relations, etc. The problem for an environmental scholar is that, while most of these jobs are not for scholars who study the environment specifically, there may also be jobs in any of these categories that fit you. Furthermore, many of us are interdisciplinary, and there is no such interdisciplinary repository. For this reason, you will have to get on the listserves. The following listserves have a large number of job postings in the environmental social sciences. Most are fairly high traffic listserves - and most of the traffic is not job postings, so if you do not wish to be overwhelmed with email, I recommend subscribing to them in "digest" form - in which you will get one email per day containing the subject lines of the day's topics - with a link to read the message:
Gep-ed - global environmental politics listserve https://groups.google.com/forum/#!forum/gep-ed
Environmental Governance - https://mailman1.u.washington.edu/mailman/listinfo/environmentalgovernance
E-Anth - Ecological anthropology http://www.aaanet.org/sections/ae/index.php/listserv/
environmental sociology http://envirosoc.org/listserve.php
Association for Environmental Studies & Sciences -https://aessonline.org/aess-listserv/
ecolog - mostly ecology, but many jobs in natural resources are advertised here as well - http://www.lsoft.com/scripts/wl.exe?SL1=ECOLOG-L&H=LISTSERV.UMD.EDU
The cultural and political ecology specialty group of the American Association of Geographers http://lists.psu.edu/cgi-bin/wa?SUBED1=AAG-CESG-L&A=1
The Political Ecology Society Listserve - http://listserv.utep.edu/mailman/listinfo/pesoemails (note that as of 2019 this links appears to be broken, but I can't find a better one, and I'm still getting emails from them. A number of newer political ecology groups are Europe-based - for example https://entitleblog.org/, and I'm not as familiar with their lists).
The Social Science Working Group of the Society for Conservation Biology https://conbio.org/groups/working-groups/social-science/sswg-email-list
Collective Action and Property Rights News (this is a program of the Consultative Group for International Agricultural Research, and thus posts alot of jobs related to international agricultural development, including many that will be of interest to environmental social scientists) http://news.capri.cgiar.org/ *note as of January 2018, this source appears to no longer be active)
DISCCRS - http://disccrs.org/subscribe - climate news & jobs (as of 2019 seems to be no longer active - they also maintain a list of listserves, some of which may be of interest) - http://disccrs.org/career
Energy Research and Social Science List (UK based, not as familiar with this one, but it looks quite active) https://www.jiscmail.ac.uk/cgi-bin/webadmin?A0=EASSN
IISD maintains a number of listserves for environmental news, and some of these listserves also contain job postings. Some of them are very high traffic, some are low, and some have alot of job announcements (generally more in the NGO/international development sector than straight up academic jobs), while some do not. If some of these listserves sound like they match your areas of interest, try them out.
You can also create alerts for academic jobs using various fixed keywords at the Chronicle of Higher Ed and Inside Higher Ed - in my experience, this was very clunky, but there are jobs advertised here that do not make it on to the lists - most typically jobs that are more straight up academic disciplinary positions (for example, a political science department might advertise for someone in American politics, with a specialization in the environment, and advertise in the Chronicle, but not be aware of these other lists).
Also, not jobs, but Terra Viva has a searchable directory of environmental funding opportunities - including conventional grants, and also fellowships, graduate assistantships, and postdocs (as of 2019 this is a paid subscription). You can also sign up to receive email alerts about new funding opportunities in your areas of interest. Here is another list of funding opportunities: http://www.aerinjacob.ca/funding--awards.html www.aerinjacob.ca/funding--awards.html
In addition, general academic jobs websites, such as those run by the Chronicle of Higher Ed and Inside Higher Ed allow you to specify searches using key terms, although in my experience, most environmentally focused jobs also end up on one or several of these listserves.
As a final note, Social Media can be a good albeit inconsistent way to find out about jobs. I sometimes see jobs on Twitter that I missed on the lists (although there is generally a high degree of overlap). Following prominent scholars in your area of interest on Twitter can thus be a good way to find out about jobs, but I think the listserves are likely to be more consistent (and much less distracting!)
If there are others that I am not aware of, please add them in the comments, and good luck on your academic job search!
Gep-ed - global environmental politics listserve https://groups.google.com/forum/#!forum/gep-ed
Environmental Governance - https://mailman1.u.washington.edu/mailman/listinfo/environmentalgovernance
E-Anth - Ecological anthropology http://www.aaanet.org/sections/ae/index.php/listserv/
environmental sociology http://envirosoc.org/listserve.php
Association for Environmental Studies & Sciences -https://aessonline.org/aess-listserv/
ecolog - mostly ecology, but many jobs in natural resources are advertised here as well - http://www.lsoft.com/scripts/wl.exe?SL1=ECOLOG-L&H=LISTSERV.UMD.EDU
The cultural and political ecology specialty group of the American Association of Geographers http://lists.psu.edu/cgi-bin/wa?SUBED1=AAG-CESG-L&A=1
The Political Ecology Society Listserve - http://listserv.utep.edu/mailman/listinfo/pesoemails (note that as of 2019 this links appears to be broken, but I can't find a better one, and I'm still getting emails from them. A number of newer political ecology groups are Europe-based - for example https://entitleblog.org/, and I'm not as familiar with their lists).
The Social Science Working Group of the Society for Conservation Biology https://conbio.org/groups/working-groups/social-science/sswg-email-list
Collective Action and Property Rights News (this is a program of the Consultative Group for International Agricultural Research, and thus posts alot of jobs related to international agricultural development, including many that will be of interest to environmental social scientists) http://news.capri.cgiar.org/ *note as of January 2018, this source appears to no longer be active)
DISCCRS - http://disccrs.org/subscribe - climate news & jobs (as of 2019 seems to be no longer active - they also maintain a list of listserves, some of which may be of interest) - http://disccrs.org/career
Energy Research and Social Science List (UK based, not as familiar with this one, but it looks quite active) https://www.jiscmail.ac.uk/cgi-bin/webadmin?A0=EASSN
IISD maintains a number of listserves for environmental news, and some of these listserves also contain job postings. Some of them are very high traffic, some are low, and some have alot of job announcements (generally more in the NGO/international development sector than straight up academic jobs), while some do not. If some of these listserves sound like they match your areas of interest, try them out.
You can also create alerts for academic jobs using various fixed keywords at the Chronicle of Higher Ed and Inside Higher Ed - in my experience, this was very clunky, but there are jobs advertised here that do not make it on to the lists - most typically jobs that are more straight up academic disciplinary positions (for example, a political science department might advertise for someone in American politics, with a specialization in the environment, and advertise in the Chronicle, but not be aware of these other lists).
Also, not jobs, but Terra Viva has a searchable directory of environmental funding opportunities - including conventional grants, and also fellowships, graduate assistantships, and postdocs (as of 2019 this is a paid subscription). You can also sign up to receive email alerts about new funding opportunities in your areas of interest. Here is another list of funding opportunities: http://www.aerinjacob.ca/funding--awards.html www.aerinjacob.ca/funding--awards.html
In addition, general academic jobs websites, such as those run by the Chronicle of Higher Ed and Inside Higher Ed allow you to specify searches using key terms, although in my experience, most environmentally focused jobs also end up on one or several of these listserves.
As a final note, Social Media can be a good albeit inconsistent way to find out about jobs. I sometimes see jobs on Twitter that I missed on the lists (although there is generally a high degree of overlap). Following prominent scholars in your area of interest on Twitter can thus be a good way to find out about jobs, but I think the listserves are likely to be more consistent (and much less distracting!)
If there are others that I am not aware of, please add them in the comments, and good luck on your academic job search!