What is the main environmental issue facing Ireland in 2015

Well, if you want to look at Ireland as an isolated island, I would say emissions of reactive Nitrogen due to agricultural intensification. We shall have to wait and see the outcome of the UN Climate Summit in Paris in November.

tphase wrote: »

presume you mean nitrous oxide?

Well...yes and no, I guess I phrased that badly.
Reactive Nitrogen encompasses a variety of compounds, so what I should've said was:
The inputs of nitrogen into Irish ecosystems eventually results in high emissions of NOx's, a term which encompasses Nitric oxide, Nitrous Oxide and Nitrogen Dioxide. These are due to the products of the nitrogen cycle which are amplified by inputs of plant-available forms of Nitrogen for increased crop yields.

Here ya go!
http://en.m.wikipedia.org/wiki/Reactive_nitrogen

tphase wrote: »

what I should have said was "I presume you mean to include nitrous oxide" (sorry, it was late....). I wouldn't consider reactive nitrogen to include N2O. In the troposphere it's quite stable with a lifetime of about 114 years. In contrast, the atmospheric lifetime of NOx (which does not include N2O) is measured in days. Not trying to be picky but the effects are different so it's important to differentiate them. I suspect it's a case of the same terminology meaning different things eg consider what a chemist and a gardener mean by 'organic'
Anyway, I basically agree with you but I would say the main issue is agricultural emissions as opposed to just nitrogen emissions (reactive or otherwise....:))

https://en.wikipedia.org/wiki/Nitrogen_oxide

Yep - I agree, I was wrong about the NOx including N2O, silly me! They're both included under the heading 'Nr' though, which is what I presume I intended to say at at 06:45, (oops). - I'm not an atmospheric or environmental scientist, but I am a chemist! (and a pedant, albeit cannot distinguish between different regions of the atmosphere)
Cool, I guess the only thing left to say to the lay person is 'emissions from agriculture', but specifically in Ireland, I would still say Nitrogen emissions would be the primary concern. At the end of the Kyoto Protocol, Ireland was actually allowed increase it's CO2 emissions by 13% relative to 1990! Nitrogen, however, is a different story. We've one of the highest inputs in the EU! (EPA)
Depending on the soil type, Nitrogen inputs can have other effects such as increasing CO2 and CH4 emissions also.
On the NOx/N2O thing:
Yup, NOx undergo photochemistry with ozone and anthropogenic gases still residing in the atmosphere since before my time!
The residence time of N2O is precisely why it's nearly 310 times the global warming potential of CO2 (based at 1, Methane = ~21). It is N2O's unreactive nature that prevents it from being removed from the atmosphere, as NOx are in dry and wet deposition. So it remains there.
So why is it so high if it's inert?
Back to GWP - the ability of a particular pollutant to force the climate relative to CO2.
N2O is IR active, and so traps heat in the atmosphere.

- Pedantic, I know, but I've OCD. :P
(also, I'm aware you may already know this, it's for others too!)