To limit warming to 1.5℃ above pre-industrial levels, we’ll need to cut global emissions by 7.6% each year this decade. It’s difficult, but not impossible.
The last time global carbon dioxide levels were around 400ppm was four million years ago. On average, the world was 3℃ warmer, but in high northern latitudes, it was up to 14℃ warmer than today.
The drop in traffic during COVID-19 lockdowns reduced global emissions. If we keep encouraging cycling and working from home beyond the pandemic, our climate goals may become more achievable.
If we had not altered the composition of the atmosphere at all through emitting greenhouse gases, particulate matter and ozone-destroying chemicals, the average temperature would have remained stable.
While it’s impossible to stop all extraction of fossil fuels now, renewable sources are already generating 25% of global electricity demand now and their contribution continues to grow.
Countries account for emissions based on all activities that happen within their territory, which means countries that export more than they import will likely have higher per capita emissions.
It is easy for people in the industrialised world to blame population growth elsewhere for environmental damage. But increased consumption is just as important – if more confronting.
James Renwick, Te Herenga Waka — Victoria University of Wellington
Earth’s has gone through major climate changes in the past. They happened on time scales of millions of years and triggered mass extinctions. Our emissions are changing the climate much faster.
Food choices make a difference to the climate impact of our diet. Every step towards eating a more plant-based diet results in lower emissions, better population health and reduced healthcare costs.
Plants take carbon from the atmosphere as they grow, but it goes straight back when they die or are harvested. There is an important difference between carbon fluxes and actual carbon sequestration.
A switch to electric transport is one of New Zealand’s key climate strategies. It will increase demand on the national grid, but might also help increase renewable electricity generation.
Under the Paris Agreement, countries have registered plans to meet emissions reductions, but the current pledges, if fully realised, would take us to 2℃ by the 2050s.
Many temperate crops require winter chilling to initiate flowering or fruit ripening, and orchards may need to shift to colder areas.
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New Zealand is a net exporter of many fruit and vegetables. While climate-change induced food shortages are not an imminent risk, some crops may be affected by rising temperatures and extreme weather.
Planes can create clouds of tiny ice crystals, called contrails, and some studies suggest they could have an a significant effect on climate.
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Globally, emissions from air travel account for only about 3% of the warming human activities are causing, but aviation affects our climate in a number of ways.
As sea levels rise, it becomes easier for ocean waves to spill further onto land.
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James Renwick, Te Herenga Waka — Victoria University of Wellington
For every ten centimetres of sea level rise, the chances of a 100-year coastal flood increase three-fold. This means we’ll have to build flood defenses or retreat from the coast.
Rapid population growth and increased consumption are now seen as the main drivers of environmental changes.
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Discussions about climate change often skirt around the issue of population growth, but it is the main driver of rising carbon dioxide levels and many other environmental changes on a planetary scale.