What a thought-provoking question!

As per my understanding, the whole world will not be flooded. Because the estimated global sea level rise is about 70 meters when all the mountain glaciers and ice caps of Antarctica and Greenland melt; however, our coastal cities would be flooded and some small islands would sink. This would result in significantly smaller land and completely different coastlines. However, scientists are still trying to calculate the exact volume of glaciers and ice caps on Earth.

Furthermore, the scientists who study sea level changes in the past, found that the Antarctic ice cap has survived much warmer times than current warming. Therefore, it is likely that all the ice may not melt completely. The main concern is that some parts of the West Antarctic ice caps and Greenland may melt completely. Scientists are still researching how, when and under what conditions this might happen.

So, the short answer to your question would be, we're still working it out!

Climate change is a global problem requiring action by many people, organisations, and countries around the world. Every action count and we are all responsible. So, although ideally all countries will work towards achieving net zero emissions, even one country achieving that goal will help to mitigate the issue.  

Those countries like Australia that have more capacity to take climate action, should show leadership in this area. This in turn will provide incentives for others to follow. Unfortunately, some national governments have argued that their contribution to the problem is too small to make a difference. But if all countries choose to let others take the burden, this will leave the global problem unaddressed. 

The good news is that we are now in a situation where the cost of taking climate change action has fallen, and the longer we wait to do so (meaning the longer we depend on fossil fuels), the more expensive it will be. At the same time, the benefits of addressing this global issue have become clearer and are indisputable (for example, lower level of air pollution, health benefits, clean water, green jobs, energy independence). As the Joel Pett cartoon says in a humorous way, “What if it's a big hoax and we create a better world for nothing?”  

Other resources can be found here:

https://astrobiology.nasa.gov/news/life-in-the-extreme-hydrothermal-vents/

Thousands of years ago, when sea levels where much lower than today, the Torres Strait was a land bridge between Australia and Papua New Guinea. Rising sea levels turned it into a series of islands. As climate change continues to cause more sea level rise, these islands will get smaller. Parts of the islands are more than 100 m above sea level, so there is no risk of the entire island disappearing. But, as the sea level rises, high tides and storm surges become much bigger problems. A storm surge is the increase in sea level that happens during a cyclone or other large storm. Sea level rise is already making the impact of these extreme events much more severe, and this will continue to get worse as the sea level rises.

This is such a good question and one that is quite tricky to answer accurately as there isn’t any exact global tally of money spent by all sectors on climate action. We only have estimates. It’s also difficult to tease out a separate figure for what industries spend, versus what governments spend. In addition to this, when we think of money spent on climate we need to think about what amount goes to mitigation and what’s allocated to adaptation. Here are some things we do know about global spending on climate change.

To transition to net zero by 2050, it is estimated that the world will need to spend about US$275 (A$428) trillion, an average of US$9.2 (A$14.3) trillion a year. We are currently far of this mark: we would need to increase annual spending by as much as US$3.5 (A$5.4) trillion from today. This figure is for spending on physical assets for energy and land use systems. We also need to consider how much money is spent on adaptation to climate change. The United Nations estimates that currently some US$50 (A$78) billion is spent on adaptation: a small fraction of what is actually needed.  Rich countries pledged under the 2015 Paris Agreement to provide US$100 (A$155) billion a year to developing countries cope with damages from climate change. Unfortunately, this pledge has not been followed through, and climate finance to developing countries has fallen well short of the US$100 billion target since this initiative began.

It’s also important to think how much it would cost if we don’t invest in tackling climate change. It’s estimated that global economic losses from unmitigated climate change could be US$15.49 (A$24.1) trillion per year. In contrast, if we do invest in transition to net zero now, the global economy could see gains of US$43 (A$67) trillion between 2020 and 2070 and an overall boost of 3.8% to global GDP.

Where could money to deal with climate change come from? Research shows that the trillions of dollars needed to deal with climate change could come from redirecting current subsidies to sectors like the fossil fuel industry. It’s been estimated that US$7 (A$11) trillion a year in planet-damaging subsidies could be repurposed to combat climate change. Overall, it’s clear that that we only stand to benefit from spending on climate action now – and that as a global community we can afford it. In fact, we can’t afford not to.

Climate change is caused by natural processes but also increasingly by human activities. The main driver of climate change is the greenhouse effect. Some gases in the atmosphere have a similar function to the glass in a greenhouse. The glass walls of a greenhouse let heat and light from the Sun in, which warms up the air inside. Similarly, greenhouse gases let the incoming heat from the Sun pass through to the Earth’s surface, where it is trapped. Many of these gases occur naturally, and natural causes of changes to the greenhouse effect include solar radiation and volcanic activity. But human activities are increasing the concentrations of some greenhouse gases in the atmosphere, in particular carbon dioxide, methane, nitrous oxide and fluorinated gases, leading to an enhanced greenhouse effect and warmer temperatures.

The main human activities causing these changes are:

1. Burning of fossil fuels such as coal, oil and gas, which produce carbon dioxide and nitrous oxide
2. Deforestation, which means that there are less trees to help absorb carbon dioxide from the atmosphere, and carbon stored in the trees is released to the atmosphere
3. Increasing livestock farming, which is problematic as cows and sheep, for example, produce large amounts of methane when they digest their food
4. Fertilisers containing nitrogen, which produce nitrous oxide emissions
5. Fluorinated gases, which are emitted from equipment and products that use these gases, such as refrigerators, air conditioners and heat pumps

While natural processes play a role in how the climate changes, what we are currently experiencing cannot be explained by natural processes alone. Since at least the mid 20^th century, humans are unequivocally causing climate change, and unless we modify how we live and how we interact with the environment around us, this will continue to be the case.

We cannot say that climate change was entirely responsible for the Black Summer Bushfires of 2019/20, but we can certainly say that it played a very important role.

2019 was Australia’s hottest and driest year on record. The combination of hot and dry weather leads to high fire risk because it produces fuel (plant material) that is exceptionally dry and easy to ignite, and it also produces extreme fire weather (hot, windy) that makes it difficult to fight the fires.

These extreme climatic conditions in 2019/20 were strongly influenced by climate change. However, the fires were also influenced by climate events that occur naturally from time to time. An example of this is that the fires occurred during an El Nino event, which is a natural climate pattern that leads to hotter and dryer weather in Australia. The effects of climate change, like hotter weather, made the natural El Nino event much more extreme.

To summarise, the Black Summer Bushfires occurred during the hottest and driest year on record in Australia, which is largely caused by climate change. Even though there were other naturally occurring cyclical climate events involved (like El Nino), the fires would have been more manageable without human-caused climate change.