How Urgent is it?
Very Urgent!The temperature of the air and the ocean is rising rapidly compared tot eh past 6,000 years, the CO2 is rising, the methane is rising, the nitrous oxide is rising, the sea level is rising, the ocean is becoming more acidic, coral bleaching is becoming extensive, the Arctic and Antarctic ice caps are melting, the permafrost is melting, the world is sing more and more power, and the use of fossil fuels continues to add CO2 to the atmosphere, making matters much worse.
NOW IS THE TIME TO ACT
(Note: we are still building this section so there will be lots more information to come.)
In this section we will explore the idea of "urgency." Just how significant is it to act now as opposed to delaying a bit and then doing something - perhaps waiting for a new invention to come along? To illustrate the point. If you are standing in the middle of the road, and are told that there is a car driving toward you at 100kms/hour, and that unless you move out of the way, you will be killed, there is a big difference in how you will react depending on how far away the car is - even though the actual impact is the same whether the car is a km away or just 10 meters away. In the first case - at a km away - the urgency to act is less than if the car is a mere 10m away. Suppose, with the car 1 km away, in addition, your young daughter is refusing to get off the road. If you wait until she decides to move, there might not be time for both of you to get out of the way. If that happens you will be faced with a decision - save yourself or save her and sacrifice yourself. That is a bit like dealing with global warming. If we act now, we can reduce the risk, but if we leave it any longer, we are putting our children and grandchildren in danger, even though we might be able to get out of the way in time.
The TimelineThe timeline for reaching global warming tipping points is still under the control of people, although the window of opportunity is rapidly closing. If we hit 2050 at 2.5 0 C and 500ppm CO 2 , the window is probably still open a crack, but if society allows the world to reach 2100 at 4 0 C to 6 0 C and 650ppm CO 2 , that window is closed without massive intervention using major coordinated geo-engineering efforts on a global scale.
During the last integlacial period where the global temperature was not much warmer than today, and CO2 was actually less, the sea level was 6m (20 feet) to 9m (30 feet) higher than today. That is enough to flood most of the major coastal cities of the world. The last time the ice disappeared from the Arctic in the summer was 100,000 years ago. It is about to happen again in the next few years.
The good news is it won't happen tomorrow. The first bad news is that unless we act now, it will happen. The second bit of bad news is that the reason we need to act now is that if we do not, those predicted events become a "locked-in" certainty, no matter what our descendants do. That causes even more sea level rise, even more drought, and the loss of freshwater resources will be severe.The really bad news is that unlike global warming in the past when there were natural built-in mechanisms to stop the warming and cycle back down to cool periods, by using the CO 2 to start the warming period, we essentially short-circuit the natural cap to the extent of warming. Without that cap, there is no limit unless humans both stop the global emissions and bring the CO 2 content back down to about 280ppm. The end result of a run-away global warming event is lethal to human life on the planet. We really do not want to let that start to happen because it would be extremely difficult or impossible to stop once it got going.
Some Background Information
How "normal" is our rising greenhouse gas levels? Is this something that happens routinely in nature? the greenhouse gas level in the atmosphere has been less than today's level for over a million years. So no - this is not "normal." The added greenhouse gas causes an increase in temperature. There have been ups and downs in temperature for sure, but compare the rate of change in the last 2,000 years. The rapid increase at the end has all happened since we started burning fossil fuels for energy and heat. The red line is the increase in temperature caused by the added greenhouse gas just since the mid 1900s! Is that scary? It seems to have risen only about 1.5 0 C since the Little Ice Age in the 1600s. You bet it is.
Still too much mumbo-jumbo?
If we keep on burning fossil fuels, using poor agricultural practices and cutting down the forests, the world will heat up to the point where the sea level will rise enough to drown most of the coastal ares, including buildings, businesses, and homes. Storm surges will make it worse. Farms in the south of the US and Mexico, as well in other warm temperate areas, will be abandoned because of excess heat and drought. Freshwater will be a problem in areas now fed from mountain glaciers (almost a billion people!). I could go on, but people will begin to be even more desperate than the poor farmers who had to abandon their farms in the Middle East causing major disruptions in Syria and surrounding nations. Already millions of people are on the move - and global warming is just getting started!
Now, not some distant future, is the time to transition away from fossil fuels, to stop cutting down the forests, to improve agricultural practices, and work on recycling and efficient energy uses.
Is sea level rise a real problem?Yes! If the temperature stays at our present level of about 10C above pre-industrial times, the sea level rose 6m to 9m. That wipes out many major coastal cities.
Are we cooked At 400+ppm CO2?The estimates range from about 40C to as much as 8 0C. If the temperature does get as high 80C above today's temperature, we are at least partly cooked! Many parts of the world would be too hot for humans to live.
CO2 is still going up. How hot can it get?That is the $multi-million question. We know from the Mid Miocene Optimum Climate period the temperature went up about 4 0C for every 25ppm CO2 increase between 400ppm and 500ppm CO2. We also know that the last time the Earth got to 300ppm CO2, the temperature was on average about 20C or more warmer than today. Suppose we take 10C for each 25ppm from 300 to 650ppm CO 2. I chose 650ppm because that is likely by 2100 unless we make a drastic change in our emissions. 650-300=350ppm. If we divide 350 by 25, we get 14. So the potential is for our average global temperature to increase from today's temperature by about 140C! That would take along time - probably hundreds of years, but it would be unstoppable if the atmospheric concentration of CO2 stayed at 650ppm. That increase in temprature would be disastrous for people, although the lizards would love it.
How high will sea level be at 500ppm CO2?Good question! If the ocean behaves like it did in the Miocene, and we are 500ppm CO2 or higher, it might melt most of the Greenland Ice Sheet and some of the Antarctic Ice Sheets. If it did that, it would take time, but eventually it could be as much as 25m to 30m higher than today. That combination of a hot world and sea levels high enough to destroy almost all coastal infrastructure would place a severe stress on human civilization as we know it.
But that's all far off in the future – right?
Nope, not all of it!We already see constantly warmer weather as the climate warms up. The Arctic is melting. Glaciers are retreating. Under-ice lakes are forming in Greenland. Storms are more intense. Salt water floods are more common in coastal cities. Drought conditions are spreading. Disease and pest vectors are already breaching previous barriers. And there is a LOT more to come if we do not take action.
No, Everything will not quickly return to normal.Just in case you are thinking that we can wait and do the changes slowly without damage because once we stop emitting excess CO2everything will quickly return to normal - Sorry that is not the case. Once we melt ice, it takes a lot of time and cold to freeze it back up again to lower the sea level back to normal. Remember to go from water to ice takes a lot more energy than just going up 10C. It took over 200 years to get this hot. On average in the past it takes about four to eleven times as long to cool down. So unless we act fast, we will have committed the world to about some thousands of years of global warming above pre-industrial temperatures.
So what should we do?
CO2 needs to go back down to 280ppm quicklyTo keep our sea level to less than 1m of rise, we need to hold the CO2 in the atmosphere at about 280ppm. We are currently at 410ppm and the CO2 level continues to rise. That means not only do we need to stop emitting excess CO 2, we also need to suck billions of tons of CO2 out of the atmosphere.
Sue the Government?
James Hansen's granddaughter and 20 other youths are so worried about their future, that they are suing the US federal government to attempt to get action going much more quickly. James Hansen is acting as the guardian in the court battle. In this video, they explain both the science and the legal rationale for their suit against the government.