YOU could be forgiven for thinking that Brexit is the only thing going on right now, but the political climate is not the only climate in turmoil. Behind the media headlines, the global climate system is changing and, for each year that this continues unabated, the odds for humanity stack up further.

Globally, surface temperatures have risen by around a degree Celsius since we started burning fossil fuels in earnest in the 1800s. But this figure masks huge spatial variation — some places have warmed much more than others. In the Arctic and parts of the West Antarctic, the figure is close to 3°C in some seasons — enough to change when and where polar ice is found, with dramatic consequences for more temperate regions. At the rate we’re currently at, we’re set to hit 1.5°C somewhere between 2030 and 2050.

This 1.5°C limit is increasingly being seen as the upper bound of “safe” climate change. A recently released report by the Intergovernmental Panel on Climate Change (IPCC), outlines the importance of staying within 1.5°C, a target also enshrined in the 2016 Paris Agreement, which commits 184 nations to stringent emissions reductions to curb warming. The consequences of overshooting this target even by half a degree are significant.

With higher average global temperatures, we can expect to see a more chaotic and less stable climate system, which will lead to more extreme weather events like drought, flooding and storms, loss of animal and plant species, thawing and melting of ice and permafrost in the polar regions and rising sea levels that could threaten homes and livelihoods worldwide.

If we continue to emit greenhouse gases at present rates, we’re on target to warm global temperatures by 3-4°C by 2100. This, the most extreme scenario considered by scientists, would carry significant risks. Remember the summer of 2003?

The heatwave of July and August is thought to have caused 70,000 deaths across Europe. This is the kind of event that we can expect to see more of, with knock-on effects on crop harvests and water resources. Patterns of rainfall are likely to change, leading to extreme flooding in some places, while causing drought in others. In short, things are going to get more extreme.

Rising temperatures and melting ice sheets may lead to global sea level rise of over a metre under this scenario. This puts low-lying and densely populated cities like Dhaka, Shanghai, Miami, Lagos and London at severe risk. According to the Union of Concerned Scientists, many cities on the US East coast and Gulf of Mexico are likely to experience fortnightly “disruptive flooding” severe enough to force people to relocate within the next two or three decades. In the UK, projected sea level rise will hit hardest in areas at risk of erosion like South Wales and East Anglia. Londoners should be worried too, since 1-2 metres of sea level rise will probably cause enough flooding to overtop the Thames Barrier once a decade by 2100.

The most sensitive systems will be affected most rapidly and dramatically. On the course we’re currently on, we may see the first Arctic summer with no sea ice by mid-century — great news for speedy shipping and oil extraction, but bad news for the climate. With 2°C of warming, summers without sea ice might occur once a decade, but, if we limit change to 1.5°C, it’s estimated to be more like once a century. The majority (70-90 per cent) of coral reefs currently around today will probably be lost with 1.5°C of warming, because the species live in a very narrow temperature range. However, if warming reaches 2°C, virtually all (>99 per cent) will disappear.

Already, as the WWF reports, humanity has wiped out 60 per cent of mammals, fish, birds and reptiles and climate change is likely to add to this devastation. Changing ecosystems will jeopardise our ability to grow crops and find new medicines, increase the risk of vector-borne diseases such as malaria and limit the livelihoods that can be derived from natural resources, which will disproportionately affect the poorest farmers, fishers and foragers.

The risks don’t just come from environmental change either. Increased environmental pressures force people to leave their homes, generating a refugee crisis elsewhere.

People are already fleeing their homes on Pacific Islands as a result of rising seas, while increased food insecurity in drought-stricken parts of Africa, Central America and the Middle East is causing a new surge of migration from these areas. Climate pressures have also been linked to conflict, with some suggesting that environmental factors fuelled the fire of existing political and socio-economic tensions that led to the Syrian war. Increased pressure on resources will lead to further migration, which could lead to an increasingly hostile and turbulent political situation and, as has been demonstrated by the Middle Eastern refugee crisis in Europe, this is likely to benefit the far right.

Unavoidable catastrophe? Not quite.

If emissions ceased today, warming would probably halt below 1.5°C, leaving us with a world largely identical to the one we currently live in. Of course, we cannot simply “switch off,” but sustained, aggressive emissions reduction could stave off the kind of nightmare scenarios that are painted above. The IPCC is clear about the practicalities. To have a “likely” chance of limiting warming to 1.5°C, we must reduce emissions to net zero by 2050, and achieve a 45 per cent reduction by 2030 compared to 2010 levels.

The longer these reductions are delayed, the more aggressive the cuts to emissions will have to be and the larger the requirement for future negative emissions technologies, like carbon capture and storage, which are not yet ready for deployment at scale. The longer we wait, the more pressure we are putting on the future use of as yet immature technologies.

Practically though, how do we achieve the kind of wholesale change required to transform society within 12 years?

Traditional measures rely on government action. Market-based solutions like carbon pricing could be effective, but the carbon price must reflect the true cost of its emission. The cost has never been high enough in emissions trading schemes like the EU ETS because of the power that industry and corporations have in determining government policy.

This same power of capital means that governments subsidise fossil fuel companies to the tune of $548 billion worldwide, while slashing comparable support for renewable technologies like wind and solar, biasing the market in favour of unsustainable energy sources. In the UK, support for an industry as ludicrous as fracking is evidence of the influence of capital. The promise of profit for a few already wealthy individuals is enough to convince politicians of the need to extract marginal fossil fuel reserves against the will of people locally and nationally and at great financial and environmental cost, rather than investing in mature, zero carbon technologies.

What is needed are nationwide schemes to generate renewable heat and electricity at the point of use, which would produce a huge number of green jobs, incentivise the use of electric vehicles and provide the infrastructure to support this and investment in a nationwide, nationalised public transport system that works for people, rather than profit.

Capitalism and climate change are two sides of the same coin.

The power of fossil fuels is built on the continued support of industries and individuals that profit from them. In the face of this almighty structural inequity it can be easy to feel overwhelmed. Never has working class solidarity and community organisation been more important. Of course we can, and must, all eat less meat and dairy, fly less and walk or cycle more, but we can achieve more than our individual actions by engaging with each other, rather than becoming the atomised, disengaged herd that capital would like us to be.

To protect itself, capital distracts us with Brexit, convincing us this is the only crisis of our time. We are pitched against each other by continued austerity and the relentless nationalist narrative around immigration that seeds xenophobia and the “us against them” mentality. The antidote is solidarity — a socialism that sees through this fragmentation and vests real power back in the hands of the people.

So, we must organise. In the streets, in our workplaces, in the pubs. But social and political change is not achieved by any one tactic. Only a diversity of approaches will force a far-reaching systemic shift. Grassroots organisation is complemented by aggressive direct action — strikes, demonstrations, blockades, the full suite of techniques — all targeted optimally to maximise the consequences for capital, to hit them in the pocket. There is no binary choice: petitions, community activism, direct action, writing to MPs, demonstrations, strikes — all have a part to play in shaping change. What is most needed though, is militancy.

The left has a responsibility to act. This is the fight of our lives. To do nothing is to condemn ourselves to a very near future of war, isolation and poverty. To act is to create something better, something stronger, something more beautiful than capitalism — hope.

Ella Gilbert is a veteran environmental activist and Antarctic climate scientist. She tweets at @Dr_Gilbz and runs a Youtube channel.