The agreement reached at the COP21 Paris climate change talks is certainly a great improvement on anything that has gone before (One paragraph at a time: how the deal was done to save the planet, 14 December). Whether it is enough to save the planet (to be more precise, save the human race from catastrophe; the planet will look after itself) is questionable. Apart from the question of actual implementation of even the agreed measures (themselves expected to achieve only a 2.7C limit) there are many factors not taken into account. Barack Obama says the deal will create "more jobs and economic growth". But growth, even "green growth", is precisely the problem. We live on a finite planet with finite resources which we are already exploiting to the limit and beyond. The aim must be to achieve a steady-state economy, with resources fairly shared, but that is incompatible with capitalism's growth imperative.

A glaring omission is the effect of the many armed conflicts currently ongoing, The money allocated to tackling climate change is still dwarfed by that devoted to the means of death and destruction, currently $1.75tn annually. These conflicts themselves contribute to climate change: the US military is the biggest single corporate user of fossil fuels, a large proportion by high-flying jets, where the warming effect is variously estimated as from 1.7 to 4.0 times that at ground level. They inhibit attempts to deal with people's real problems, the effects of global warming among many others. Mass migration, from a variety of causes including conflict and climate change, is another major problem that is ignored in the Paris agreement. There is still a very long way to go to ensure the future of the human race.

Frank Jackson

Former co-chair, World Disarmament Campaign

• The Paris accord has been hailed as a diplomatic triumph because the alternative is too awful to contemplate. Nevertheless the atmosphere does not respond to political craft and strategic compromise, it only responds to the laws of physics which are uncompromising and potentially lethal for most species on Earth, including our own.

All of the really tough decisions – such as carbon taxes, country-specific limits and financial penalties – have been shelved, which will allow countries such as India, China and even the UK to carry on burning fossil fuels while paying lip-service to the need to reduce emissions. Instead the goal of 1.5C and even 2C will now rely on unproven and currently non-existent technologies such as nuclear fusion, carbon capture with storage or carbon negative technologies. I pray these will come in time but how many people would get on a flight in the hope that someone can defuse the bomb before it blows up?

Dr Robin Russell-Jones

Stoke Poges, Buckinghamshire

• While the agreement on tackling climate change is welcome, the big test, and the most challenging, will be the implementation. There are substantial business opportunities here, with countries supporting research and development into alternative energy and energy saving being the winners.

In order to develop this commercial opportunity and contribute to global emission reduction the UK government needs to reverse some of the decisions taken since it came to power. These include: divesting from renewables: privatising the Green Investment Bank; performing a monumental U-turn on the UK's £1bn carbon capture and storage (CCS) competition; reducing subsidies for improving energy efficiency; reducing the requirement for developers to build energy-efficient homes; making fracking easy to achieve and windfarms difficult; and continuing to subsidise fossil fuels.

The UK could be taking a lead, and developing a substantial commercial advantage, instead of backtracking on everything the coalition achieved.

David Becket

Newcastle-under-Lyme, Staffordshire

• The Paris climate talks followed a pattern that is familiar in international environmental negotiations. At the start of the conference tough commitments and ambitious targets were proposed, including on forest conservation and the transfer of environmentally clean technology to developing countries. Over the next two weeks many of these were weakened with caveats and, in some cases, quietly abandoned as delegates edged towards a politically acceptable compromise. This is the so-called convoy principle: everyone stays together, but all move at the speed of the slowest. Most disappointing of all is the failure to agree legally binding greenhouse gas emission reduction commitments. Without this, the pledge to limit the global temperature rise to less than 1.5C above pre-industrial levels remains purely aspirational.

David Humphreys

Reader in environmental policy, Open University

• The key phrase in Bill McKibben's piece (Climate deal: the pistol has fired, so why aren't we running?, 14 December) is "You have to raise the price of carbon steeply and quickly", or else the necessary switch to renewable energy will not happen.

In other words, people have to vote for much higher petrol prices, much higher gas and electricity bills and far more expensive air travel. Or, which would be equally unpopular, we could ration