Wrth siarad am yr amgylchedd - mae'n golygu un peth, newid hinsawdd.
Mae newid hinsawdd yn digwydd nawr. Roedd pob un o alwadau brys tyngarol y Cenedloedd Unedig ym 2007 ag eithrio un yn cyfeirio at hinsawdd.
Mae newid hinsawdd yn dwysau anghydraddoldeb cymdeithasol. Gwledydd tlawd sydd yn cael eu heffeithio fwyaf, ac o fewn rheini, y cymunedau a'r pobl tlotach fydd yn dioddef. Ond ar draws Ewrop ac yng Nghyrmu, gall swyddi fod yn y fantol mewn sectorau fel ffermio a thwristiaeth.
Rhaid i ni gyd wynebu'r realiti a newid y ffordd rydyn ni'n byw ac yn edrych ar y byd.
Gall a rhaid i Ewrop chwarae rol arweiniol yn y frwydr yn erbyn newid hinsawdd. Serch hynny, roedd Cyngor yr Undeb Ewropeaidd ym Mrwsel yn ddiweddar yn afnon neges hollol wahanol - rydyn ni wedi clywed cymaint o arweinwyr yn cyhoeddi eu ymroddiad i bolisiau radical ond doedd dim tystiolaeth o'r brwdfrydedd hynny yno.
Yn hytrach, roedd bargeinio gwyllt am eithriadau o'r rheolau a galwadau am gyfaddawdau o dan unrhyw gytundeb rhyngwladol emissions. Ar amser tyngedfennol pan rydyn ni gyd yn ceisio chwarae ein rhan. Mae'n arwydd gwael iawn bod arweinyddion Ewrop yn ceisio optio-mas o'r cytundeb - a hynny cyn ein bod ni hyd yn oed wedi cael y cytundeb newydd.
Profodd y cyfarfod yma bod buddiant economaidd yn dal i gael ei weld fel rhywbeth sydd ddim yn gysylltiedig ag amddiffyn yr amgylchedd ond mae'r ddau yn mynd law yn llaw. Mae nhw'n methu ymgydio yn yr her sy'n ein gwynebu.
Ble mae'r gweithredu brys? Edrychwch ar realiti'r sefyllfa presennol. Mae gan yr UE darged o dorri ugain y cant o allyriannau nwy ty gwydr erbyn 2020. Ym mis Mai y llynedd, cyhoeddwyd adroddiad ar y cynnydd hyd at 2005. Roedd yn dangos taw dim ond 2% oedd y gostyngiad mewn wyth mlynedd, ymhell o gyrraedd y targed. Mae hynny'n galw am ymateb brys a chydweithrediad difrifol er mwyn rhoi pethau nol ar drac.
Dyna pam mae ymroddiad llywodraeth Cymru'n Un i dorri 3% mor bwysig.
Mae gan Cymru y potentsial i fod yn arweinydd rhyngwladol/byd-eang ar taclo newid hinsawdd ac i gymryd cyfrifoldeb dros ei dyfodol ei hun. Bydd Comisiwn Newid Hinsawdd Cymru, rwyf yn aelod honno, yn gallu datblygu'r polisiau newydd yma a chreu cytundeb eang ar y ffordd ymlaen yn cynnwys rol pobl Cymru. Dylai taclo newid hinsawdd i leihau ei effaith ar yr amgylchedd, ac ar gymunedau, ac economi Cymru, fod yn un o flaenoriaethau Llywodraeth y Cynulliad. Fel gall Senedd Ewrop wneud ar lefel Ewropeaidd, gall lywodraeth y Cynulliad wneud ar lefel cenedlaethol, a bydd y Comisiwn hwn yn gyfrwng i hyn.
Gall pob un ohonon ni wneud ein rhan. Ac os edrychwch ar safle we Cyfeillion y Ddaear, ac fe welwch ynghyd â 17,860 o gefnogwyr, rhai o feibion Casnewydd y Goldie Lookin Chain yn cefnogi'r ymgyrch Big Ask am ddeddf hinsawdd cryf.
Rydw i fy hun wedi gwneud dwy addewid yn blynyddoedd diwethaf i wneud un trip mewn pedwar ar dren yn hytrach nac hedfan ac i ddefnyddio fy mhleidlais bob amser i atal newid hinsawdd ac i gefnogi 25% o arbedion ynni erbyn 2020. My f'ymrwymiad cyhoeddus yn fy atgoffa i, ein bod ni, fel gwleidyddion angen bod yn fentrus i wynebu'r sialens.
Doing that small thing let to more and more involvement and to me joining Plaid Cymru, which is the natural home for people who care about the environment and about what we now call sustainability - not living today as though the planet belongs to us - without a thought for future generations.
I soon realised that campaigns I supported locally, like the campaign to get potentially dangerous coal tips from the Rhondda was the same campaign as the one for the global environment. We often say "think global, act local - but it's true. And it's truer than ever today.
I have just had my attic converted and insulated - a good thing to do in terms of energy efficiency anyway. But I thought about the best environmental way to do this. I had it insulated with sheep's wool from a factory newly located in Rhyl with the help of the Assembly government. Not only is it a natural product - and there's no shortage of sheep in Wales - but it was easier to install and just as effective as the alternative. It was a bit more expensive, but the alternative is a million times more expensive in environmental terms.
And I'm proud of Plaid Cymru councils in moving forward the environmental agenda. In Caerffili Plaid offered financial incentives to builders to build homes with better insulation and using green energy. And Gwynedd has a Green Transport Strategy with things like lift sharing and supporting video conferencing.
In the 2006 Living in Wales survey done for the Assembly, 81% of households had recycled paper, glass, plastic or cans; 47% had bought goods which used less energy; and 30% had cut down on using the car for short journeys. People want to change. People want to make a difference.
And one issue that affects so many in Wales is waste. This is where our councils have had real influence. It was a Plaid Cymru council in Rhondda Cynon Taf that closed the Nantygwyddon Landfill Site, as we promised, and introduced one of the first kerbside recycling schemes in its place. We made one of the worst authorities into one of the best. The closure was helped by a petition to the European Parliament.
We are debating the new waste laws in the European parliament at the moment. We are trying to get a 50% target for recycling household waste - because the amount of waste we produce every year is going to grow by a quarter again in Europe by 202.
If we achieved that 50% of recycling our waste, it would save 247 million tons of C02 annually - the equivalent of taking 87 million cars off the road every year.
And speaking of cars, I would like to congratulate the Economic Development Minister for rejecting the proposed A494 seven lane road in Flintshire on environmental grounds.
While we need binding international agreements and a lead from governments, we all have to play our own part too in fighting climate change. For myself, I have made two public pledges. One - to make one in four of all the many journeys I make by train rather than flying. Secondly, every time I vote in the Parliament I will give priority to fighting climate change.
My public commitment reminds me that, as politicians, we have to be bold to face the challenge and live up to the demands of the situation.
I got involved in environmental issues before I got involved in party politics. My first political action was when I was in school. I saw a documentary on television about how the killing of whales was endangering the species. I mean the mammals, not the country. that came later! It disturbed me so much that I wrote my first letter and signed my first petition. Little did I think at the time that that action would lead to what I am doing today. It raised my own awareness that we all have a responsibility and a duty to act - however insignificant it seemed that doing that was at the time. It was doing something. Doing something is always better than doing nothing - and it does make a difference.
But while we need to improve our recycling rates, the first priority must be to stabilize the amount of waste we produce and then set targets to reduce that waste. Stabilizing waste would save us over a billion tons of greenhouse gases by 2020. We have to get our priorities right - stop creating rubbish and not keep churning it out and then having to deal with the problem of how we get rid of it.
It's a scandal that people in communities all over Wales have to suffer now with the problems of waste. Next week I will be welcoming campaigners to Brussels from the Hafod Environmental Group - putting their case against the Hafod landfill site where they have been running a very effective, high profile campaign. We wish them every success.
Campaigners against the LNG terminal and pipeline in Wales will be coming back to give further evidence in the same Petitions Committee meeting. In fact, there's a bit of a Wales takeover in Brussels next week! We also have Assembly Members coming over to Brussels to see how our petition system works and to report back to the Assembly's own petitions committee. The dedication and commitment of these people who will not give up the fight and who are taking their case to the highest levels is a reflection of the strength of feeling all over Wales.
For decades Plaid Cymru has talked about the importance of our environment - people used to take little notice. But the environmental debate crystallizes everything that we believe and everything that we stand for as a party. It means keeping communities alive - keeping post offices open, supporting agriculture and the rural economy, opposing nuclear weapons, greening the valleys, creating new jobs, securing the future of our languages and fighting poverty. Plaid Cymru has long recognised that the fight for the future of Wales was at one with fighting for the future of our planet. That is true now more than ever. Our role is to bring together and provide leadership to the forces who work for local and global justice.
We are starting a debate with the people of Wales on the future of our nation and its role on the international stage - the same kind of debate that's taking place in smaller countries across Europe. That debate will result in change which is critically needed to meet the global challenges we face. A future where every nation is equal and where every person is equal. A future where we work together to ensure our very survival. Time is running out.
Jill Evans ASE