JCM - New version available

JCM continues to evolve, although a new version was not posted for a long time on this website.
Recent developments (2015-16) include:

• Demographics module with 5yr age structure for each country, flexible options, feedbacks.
• Migration module with flows between countries, options for future
• Economic growth module with capital, investment (connecting chain demographics => energy etc.)
• Energy package (Electricity module developed IVIG Rio 2011, other sectors incomplete)
• New SSP scenario data module, to explore scenarios and replace role of old SRES
• Update of pledges consistent with the UNFCCC COP21 Paris Agreement
• scripts for Probabilistic equitable pathways analysis (developed IVIG, Rio)
• scripts for Probabilistic 1.5C/ 1.75C stabilisation scenarios
• Scala code blended with java, new sbt build structure
• SVG export (examples here)

These were applied to some Conference presentations in 2016

---

Having recently made some effort to tidy up and document the new modules, I place here a new zip package

JCM_May17_pack.zip (18.8MB)
To run it, just unzip and click on jcm-16.0.jar (assuming Java v8+ is already installed on your system).
The documentation (labdoc) and source jars are included, as are others with data.
Please be aware, these new jars are not packaged to pass security hurdles (which needs more work).
So this package is provided for experts who already know and trust me,
as you may need to disable security hurdles (how depends on your system - eg on Mac a ctrl-click helps).

---

Reasons I didn't update JCM online for a long time include:

• Java issues - Oracle made it harder to open a java app using webstart, adding extra security hurdles.
• Incomplete update - some modules (e.g. sea-level rise) are clearly outdated so could be misleading
• Missing links in the chain (to generate rather than interpolate scenarios) - particularly energy and landuse
• Loss of my old institute site and SVN source-code server
• Other life challenges (see my home page)

It's hard to complete a package ready for general (unspecified) users, as I don't know how you will use it - there are hundreds of plots and parameters and infinite combinations to test. Often it seems, the climate changes faster than our science tools can keep up. New modules, developed for recent research, are not yet so user-friendly or well documented. Changes in java and computer OS change also pose challenges for packaging a public app. So I can't promise when a new "complete" updated documented user-friendly public version will be posted here.

Nevertheless, if you are already an expert using JCM, familiar with climate science and policy, and willing to experiment, you could probably use the newest version as it is. In this case please contact me and I'll send you the latest package.

Also please contact me regarding how you might like to use JCM in the future, what would be your priorities for its development? For example, prioritise teaching (simpler, demos) or research (scripts, probabilistic etc.) applications? Focus more on socioeconomic scenarios, physical science, or impacts? Can you help support my development of JCM?

One reason JCM remains useful for research (and potentially for teaching), is that its projections were quite ahead-of-the-curve - being the first tool (since 2003) adapted to probabilistic peak+decline multi-gas stabilisation scenarios (long before RCPs and 1.5C pathways were fashionable), while also incorporating intelligent guestimates for short-term emissions and socioeconomic trends (so as I update real data, I find it makes remarkably little difference to the curves!). In general, the biggest challenge for climate science remains not the decimal places, but its communication, the interface between models and people, for which JCM was especially designed to help.

So please send me encouragement and keep revisiting here to check for a new version.