Engineering has a very large number of sub disciplines, but the general categories are usually listed as civil, mechanical, electrical, and chemical. A few others that sometimes are considered top level categories are cost, biomedical, and systems engineering. If someone thinks another should be added, I'd not quibble.
Engineering is still a very important human activity, but as with all other human endeavors, needs to be marshaled wisely, instead of being yoked to the short term profit driven economy we now "enjoy". Even from the long term view, our ability to take raw materials, and through methodical steps, fashion all manner of artifacts is amazing. During this fossil fuel enabled bonanza, we have been able to create millions of items, devices, and structures to make our lives easier.
As we face the end of cheap energy, the end of fossil fuels, and the general decline in easily extracted raw materials, we are on the cusp of a new phase in human history, and a large challenge in fashioning the artifacts that enables us to live in reasonable comfort.
So how will the engineering professions have to change? What do you do when the dozens of manufacturers ready to supply any component you need for your design are no longer there? What do you do when the advanced materials and techniques are no longer economic or even available?
I've begun a list of the new parameters that future engineers will need to consider and take in to account for their designs. This list is more on the technical side of things, and assumes that the ethical, sociological, environmental and systems thinking parameters are already a given. ( They are not yet, but that is a whole other post)
For that matter, will we even have "engineering" in the far future, meaning design using stress analysis, calculus, other forms of higher math, or will our built environment and artifacts be done at the level of craftsmen and passed down experience? I think for a generation or two at least, we'll have engineering, but it will have to change with the newly prominent parameters.
What are the new design parameters? How far down the road are they useful and relevant? How quickly will we be needing these new approaches?
In no particular order, here are some.
corrosion- Right now, nearly all ferrous things are just assumed to rust away as part of the natural way of things. Everything from ocean going ships to fencing to pipelines to cars are given some level of corrosion protection, but not enough to extend their lives beyond years or decades. Certainly not centuries or indefinitely. As iron ores and mining of same reach lower concentration levels, the continual input of new steel will end. We will be left with what we've refined, and must marshal it carefully. Any design will need to minimize the steel used, and make it very protected from rusting away. It would be a damn shame if we slid back to the stone age a couple centuries from now simply because we frittered away our iron.
longevity- Current economics dictate that many items are made to last about a day longer than the warranty. There will need to be a reevaluation on which items can truly be thrown away, made from renewable, quickly fashioned materials, versus items that have a lot of embedded energy, and should be made to last a very long time. There are old farm tractors made decades ago, that are still sound and operational, as they were built to last, and just need periodic maintenance and replacement of small components. Newer tractors have electronics, computers, and have had the weight trimmed to minimize cost, at the loss of longevity. They won't last as long without ongoing high tech support.
design for disassembly, maintenance, repair- this goes hand in hand with the longevity point. It also adds the issue that things should be repairable by the user, and not some tech center that will replace much more than necessary, just to do it quickly. The current approach makes sense when labor is more expensive than replacement parts, but that will not be the case in the future. This approach to design may well mean first cost is greater, but life cycle cost is much less. In the future we are entering, life cycle costs will predominate, not first cost.
design for renewable inputs only- where possible, some things should be designed from natural materials. This will limit the possible designs, but function will once again govern rather than form. Folks like Calatrava or Gehry will not be getting commissions. One can look at the amazing cathedrals and stadiums that were built hundreds or thousands of years ago to see that there is still much that can be done with stone and wood.
design for technology suites that won't domino- While it is hard to predict which ones with certainty, some technologies and fabrication techniques will be more likely to become impossible or vastly more expensive. Artifacts in the future should be designed so that they are not prone to single point failure in the supply chain. If semiconductor chip fab ends, then anything using them, even if for a simple sensor, might fail if this one single component is critical for function, so technology selection needs to consider only robust and simple components.
design for simple fabrication techniques- The extremely advanced fabrication techniques we have now are dependent on being part of a fully functioning industrial economy, so it's not just materials getting scarce, fab capabilities will likely degrade as well.
design for intermittent or batch production- Many parts of our industrial ecology are designed to work 24/7 to make full advantage of the capital investment, and because many processes do not lend themselves to lots of stops and starts. Oil refineries and power plants run for months on end, only stopping for preventative maintenance. Factories, food processing, transportation, heck, everything in our society stops and starts whenever it chooses, because electricity and fuels are ready 24/7. If one starts relying on solar power for heat and or power, then one is forced in to the daily batch cycle, or providing very expensive storage and the associated additional conversion losses. Whatever industry we may have in the future will need to scale to the available solar time frame and energy density.
design for easy bio/tech split- ( McDonough and Braungart)- in their book "Cradle to Cradle", they point out how much of our environment pollution problems are because we mix the technical and biological ecosystems, causing it to be very difficult to recycle or compost. Design needs to keep these two material streams easily separated after an artifact has reached the end of its useful life. Europe is much further along in this area than the U.S. In essence, this concept takes recycling to its full closed loop conclusion.
I will continue to add more of these as they occur to me, but this is already a seismic change in what engineers normally have to consider in designing things.