Even the world's largest CO2 emitters are suffering the effects of climate change. So what's stopping countries like Germany, India, Saudi Arabia, the US and China from changing tack and going green?
A drastic reduction in emissions is needed to avert catastrophic global warming. And it's needed fast, say climate scientists. Global greenhouse gas emissions must fall by 7.6% each year over the next decade to limit rising temperatures to the 1.5 degrees Celsius (2.7 degrees Fahrenheit) threshold outlined in the Paris Agreement, a UN Environment Program report warns.
Reducing emissions must be a global effort. But some nations emit far more CO2 than others. From industry to infrastructure, resources to development, and population to politics, there are different reasons for these countries' high carbon emissions. But why is it so hard to cut back on carbon and make progress on climate protection?
Germany: Cars and coal
A decade ago, Germany's plan to move to renewable energy positioned the country as a pioneer in the fight against climate change. But its climate protection efforts have stalled, and Germany is still a major contributor to global CO2 emissions.
Fossil fuels make up 80% of Germany's primary energy consumption, according to government data. Some 22% of that comes from coal. The country relies on black coal and lignite to maintain a steady energy supply alongside fluctuating renewables.
The industrial and transport sectors are also contributors to Germany's high CO2 output. The nation is one of the world's largest car exporters, and the strong car industry lobby has in the past led Germany to pursue less ambitious targets when it comes to reducing emissions.
Under pressure from an increasingly climate-conscious electorate, the German government has promised to shut down all coal-powered plants by 2038. It has also pledged to raise fuel prices in an attempt to reduce transport emissions.
But with Germany likely to miss its CO2 reduction targets for 2020, the government's latest climate policies have been slammed as too little, too late. More than half of Germans surveyed by public broadcaster ZDF said the measures did not go far enough.
USA: Political issues
The power and transportation sectors are the two largest contributors to CO2 emissions in the US, according to figures from the country's Environmental Protection Agency (EPA). More than 80% of US energy consumption comes from fossil fuels.
While the US is the second-largest CO2 emitter globally, it's also the country where climate change denial has most taken root. Six% of the population believes the climate is not changing — the highest figure among 28 countries surveyed in a recent YouGov poll. Another 9% of Americans believe the climate is changing, but that human activity is not responsible.
US President Donald Trump has himself denounced climate change as a hoax and started the official process of pulling the country out of the 2015 Paris Agreement, a global pact aimed at limiting global temperature rise. The country was recently ranked worst in the world for climate protection efforts. "Climate policy there is going backwards," said Niklas Höhne, one of the authors of the Global Climate Protection Index report, published by environmental groups Germanwatch and the NewClimate Institute.
Saudi Arabia: An oil-dependent economy
The Gulf state is the world's largest oil exporter and its economy relies heavily on the oil industry. Ambitious pledges to diversify by investing in renewables have resulted in little progress.
The country also has high per capita emissions at 16.3 tons annually compared to the global average of around 4.8 tons per person per year. This is partly due to people needing to cool their homes. The desert country faces extreme temperatures, water shortages and increasing desertification. A recent YouGov poll found that the majority of Saudis believe climate change would affect their lives. Of those surveyed, 41% believed the issue would have "a great deal of impact."
For years, critics have blamed Saudi Arabia not only for its high contributions to climate change but for blocking attempts to tackle it. Speaking at the current climate summit in Madrid, Jennifer Morgan, executive director at Greenpeace International, accused the Saudi government — along with others like Brazil — of trying to weaken UN agreements aimed at slowing global warming.
India: Growth and development
India is the third-largest carbon emitter globally. But its CO2 output is far lower than both China and the US. And when India's huge population is taken into account, the picture looks different again. Its emissions per capita are actually less than half the global average. That's partly because a large proportion of the population lives in poverty — more than a quarter, according to the UN's latest human development report.
However, the country is developing fast. Its energy demands are rising, as are its emissions. The country meets its energy needs mainly through coal. Fossil fuels account for almost three-quarters of India's total energy consumption, UN figures show.
The government has promised to change that, saying India aims to generate 40% of its energy from non-fossil fuel sources by 2030.
Read more: COP25: Developing past fossil fuels in India
But investors are put off by the initial high financial outlay required for renewable energy infrastructure, despite the long-term savings. Many argue investment in green energy projects should also come from industrialized nations to boost sustainable development.
Until energy produced by renewable sources like wind and solar can be stored cheaply and efficiently, the country will still need to rely on coal power.
China: Embedded emissions
China is the largest carbon emitter globally. But it also has the world's largest population. China's annual per capita emissions are growing, and at 6.4 tons they are already higher than the 4.8-ton global average. But this figure pales in comparison to the per capita emissions of other big emitters by nation, like the US (15 tons) and Saudi Arabia (16.3 tons).
As the world's top manufacturing nation and the largest exporter of goods, embedded emissions — CO2 embedded in exported goods — are a big issue for China. Because CO2 emissions are generally measured by the amount a country directly emits, nations can reduce their emissions by outsourcing carbon-emitting production abroad to places like China.
However, China also benefits from this means of emissions measuring. While it has cut the share of coal in its own energy mix, it invests heavily in coal-fired power projects around the world.
But China has made ambitious climate promises, aiming to bring emissions to a peak by "around 2030" and further reduce its use of fossil fuels in the next decade. Progress in reducing air pollution also offers hope that the leading CO2 contributor could achieve a shift towards climate protection in future.