The spatial distribution of ocean regions and continents is unevenly arranged across the Earth's surface. In the Northern Hemisphere, the ratio of land to ocean is about 1 to 1.5. The ratio of land to ocean in the Southern Hemisphere is 1 to 4. This greater abundance of ocean surface has some fascinating effects on the environment of the southern half of our planet. For example, climate of Southern Hemisphere locations is often more moderate when compared to similar places in the Northern Hemisphere. 
From http://www.physicalgeography.net/fundamentals/8o.html 
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Is anthropogenic global warming going to affect the northern hemisphere more than the southern hemisphere? Is there an anthropogenic warming?
These are difficult questions to answer simply. It’s complicated, yet simple — and we can say YES to both questions — as observed. 

First, under the presence of more CO2 in the atmosphere, the surface of the planet is warming up. CO2 is a warming gas under two main specific wavelengths of infrared emission from the sun. It's similar to water being warmed up in a microwave oven, except infrareds have more energy than microwaves... As it warms up, the CO2 warms up the atmosphere. Simple again.

It has been calculated that without any CO2 as a warming gas, the average temperature of the planet would be minus 35 degrees Celsius under present conditions (considering other gases, Milankovitch cycles, natural seasonal variations, etc). The level of CO2 in the atmosphere is thus critical in maintaining, reducing or increasing the temperature at the surface of the planet, overall.

Second, some EXTRA CO2 above the natural maximum level of 300 ppm has been emitted into the atmosphere by human activities, mostly from burning fossil fuels. Since the industrial revolution of the 1850s, humans have pumped more than 120 ppm of CO2 above the maximum recorded natural level. Coal, oil and gas being the main culprits.

The natural CO2 cycle between 180 and 300 ppm is maintained by animal and plant activities, especially photosynthesis (without which we would be cactus) and animal breathing — and ocean absorption of CO2. Presently, these natural conditions CANNOT absorb much of the EXTRA (anthropogenic) CO2, though some of it (uncounted in the atmosphere) has been absorbed by the oceans, turning them "more acidic".

Third, the rule of thumb is that the northern hemisphere will warm up more. First because of its oceans/land ratios and second because it is the largest reservoir of atmospheric CO2 and where most of industrial CO2 emissions have been produced. Though Cape Grim observatory in Tasmania has recorded 400 ppm of CO2, the concentration is highest in the northern part of the planet (on average between 2 and 5 ppm extra). The highest concentration of CO2 is above the Arctic. The Arctic is warming up fast.

GENEVA, May 26 [2014] (Reuters) - Carbon dioxide levels throughout the northern hemisphere hit 400 parts per million (ppm) for the first time in human history in April, an ominous threshold for climate change, the World Meteorological Organization said on Monday. 
The 400 ppm level in the atmosphere, up 40 percent since wide use of fossil fuels began with the Industrial Revolution, is rapidly spreading southwards. First recorded in 2012 in the Arctic, it has since become the norm for the Arctic spring. 

But the "global" warming of the northern hemisphere will not be homogenous, due to climatic zoning and other factors such as continental position and the slowing of the Gulf Stream, which keeps Europe generally warmer than Canada on the same latitudes. 
This is likely to create more severe European cold winters while continental summers will be most likely hotter. As well, while the Arctic warms up, a bitter winter cold "vortex" can form south of Canada in winter, in the northern eastern part of the USA. Meanwhile, summer forest fires will break out in Greece, Spain, in California and in Alaska. As the planet warms up, there will be more of this — due to more hotter and drier conditions, while occasional flooding will be severe from sudden storms.

Meanwhile in eastern Australia, despite having been in a La Nina event (cooler humid climes), a massive drought has settled in over the last few years. And it's likely not to improve as we're moving into an El Nino event (warmer dry climes). Bushfires have raged in the last few years as well. The chance of cyclones has gone up, bringing in destructive winds and flooding rain, that usually bypass the drought areas. We are advised today that Sydney might experience a major dust storm this week. 

All these weather events are getting stronger and more frequent under present global warming conditions. One other factor to be taken into account is the zoning of the atmosphere in various convection currents: equatorial, tropical, temperate, polar... These zonings will most likely be disturbed to a point at which the atmosphere will behave chaotically. This point of chaos has been estimated by some scientists to happen by the year 2045. Gus's own prediction is 2032. 

CO2 concentration fluctuates daily, but with an upward trend. Since the 400 ppm threshold was first crossed in 2014 in Hawaii, the highest recorded was 412.60 ppm on May 14, 2018 — 407.31 ppm was recorded on Aug 12, 2018. Roughly 2 to 3 ppm added per annum, despite our (piddly) efforts at reduction of emissions.
Cape Grim first recorded 400 ppm of atmospheric CO2 in 2016. Today it is 404.7 ppm. (328.8 ppm in 1976). The latest greenhouse gas (GHG) data is updated monthly from Cape Grim, one of the cleanest air sources in the world where the observations of other atmospheric warming gases, NOx and methane, have not varied much since 1976.
Meanwhile, emissions of methane, have surged in the northern hemisphere, during the last decade. Scientists have been surprised by the surge, which began around 2007 and was boosted further in 2014 and 2015. Concentrations of methane in the atmosphere over those two years alone rose by more than 20 parts per billion, bringing the total to 1,830ppb (parts per billion). 
Some methane comes from melting permafrost and from melting ice. Some comes from animal husbandry. This is a cause for alarm as methane warms the planet more than 20 times than similar volumes of CO2.

EXTRA emissions of CO2 – the main component of manmade greenhouse gases in the atmosphere – have been tapering off slightly, but the emissions are still rising. As the world attempts (not much in Australia unfortunately) to control greenhouse gases, we have somewhat also failed to take account of the rise in methane.

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The southern hemisphere of the planet has the biggest reserve of “cold” in the form of fresh water ice on earth: 61 percent of all fresh water on the Earth is held in the Antarctic ice-sheet — an amount equivalent to about 58 metres of sea-level rise should it all melt — not accounting for water heat-expansion. Can it all melt? Of course. Times have happen before when there was no ice on the surface of the planet. What induced these warmer times? Many factors, including the natural surface carbon equation (CO2 in the atmosphere) being different to that of today. The fossil/geological records show that temperatures were up to 8 degrees above the present in the early Pliocene. Just add this EXTRA 8 degrees Celsius to your present comfort level and feel winters like summer and summers like hell.

Sea level would rise about 6 metres, should the entire Greenland ice-sheet melt. Is the Greenland ice melting? Yes. Mostly in bursts. in July 2012 nearly all of the veneer of surface ice atop the island's massive ice sheet had thawed (this means that the surface was exposed to some quite warm air). This was a record in more than 30 years of satellite observations, according to NASA and university scientists. Presently, the climatic conditions in Greenland are similar (and beyond) to the mini warm period of the early middle ages.

In the last few years, "warm" oceans' influence on glaciers has come to the forefront, as scientists now recognise this as a major—if not the primary—contributor to ice loss in both Greenland and parts of Antarctica. There is an increase in the amount of warm water that many polar glaciers are exposed to. It is as simple as the fact that climate change is causing the oceans to warm, in addition to the outside air, and some of it also involve the complex ways climate change is believed to be affecting atmospheric patterns, winds and ocean currents that carry warm water around the world.

The Arctic sea melt would not change the sea level, as it is (mostly sea) ice already “floating” on the ocean. 
As the ice melts, it cools sea water and cools the atmosphere through aerial convection currents. Thus the full effect of global warming appears to be DELAYED, hidden by the ice melt.
The rule of thumb is that water MINIMUM volume is at 4 degrees Celsius. Ice (frozen water) is about 110 per cent volume of water. Thus ice “floats” and ice will explode full water bottles. Should all the oceans "freeze", the icy sea level would be about 120 metres above present.
Icebergs are freshwater ice, thus float higher on sea water (88 percent submerged) that they would on fresh water (90 percent submerged). This is why a Plimsol line on a ship has two levels of maximum allowed immersion: one for sea water and one for fresh water.
As water warms up (up from 4 degrees Celsius) it expands. Should water cool from 4 degrees Celsius it also expands and at 0 degrees Celsius, it expands 10 per cent and forms ice. The oceans are complex "temperature reservoirs”. 
The surface layer of oceans are warmed up by the sun. There is a boundary layer called the thermocline between 500 and 700 metres deep on average. Below this level the temperature of the water drops sharply.
The average temperature of the ocean surface waters is about 17 degrees Celsius (62.6 degrees Fahrenheit). Much of the deep ocean water is between 0-3 degrees Celsius (32-37.5 degrees Fahrenheit).
Researchers looking at corals in the western tropical Pacific Ocean have found records linking a profound shift in the depth of the division between warm surface water and colder, deeper water traceable to recent global warming. Deep diving probes have also indicated major changes to the thermocline temperature gradients, due to global warming.

At the equator, the thermocline is generally 25 to 200 metres (82 to 656 ft.) deep in the equatorial regions and up to 1,000 metres (3,281 ft.) in the subtropics.
The existence of a strong and shallow thermocline in the tropical oceans has important implications for climate. In the equatorial Pacific Ocean, westward surface winds lead to an accumulation of warm surface water in the west, depressing the thermocline there and raising it to near the surface in the east. The shallow thermocline in the east enables cold, nutrient-rich water to be mixed upward into the surface layer. Every few years the thermocline in the eastern equatorial Pacific deepens in association with an El Nino event. The surface temperature of the eastern equatorial Pacific Ocean increases, and biological productivity decreases. The warmer surface temperatures associated with El Nino affect atmospheric circulation in the tropics and alter weather patterns throughout the world. 

During the early Pliocene period, between 4.5 and 3 million years ago — the most recent period with global temperatures significantly higher than today — the eastern Pacific thermocline was deep like it is during a modern El Nino event.
So what does this mean? Is the present warming "natural" and in line with the early Pliocene? No. Conditions were different. Under the influence of the so-named "Milankovitch cycles" that measure the rotation/eccentricity of the planet's axis — during the Pliocene, a period of high frequency and low amplitude oscillation in the 41,000-year cycle of Earth's obliquity changed to the low frequency and high amplitude oscillation of the 100,000-year period in the orbital eccentricity — leading to the Pleistocene glacial/interglacial cycles. During the Pliocene, apart from the early years, climate became cooler, drier and seasonal, similar to our modern climates.
The present Milankovitch cycles are more or less neutral on our present climatic conditions, but their trend would lead in the long run to a cooling of the planet, contrarily to the observed sharp warming since the 1850s when we started to burn fossil fuels on an industrial scale, as studied by Arrhenius.
So where to from here? After having studied all the possible agents influencing our climates, anthropogenic CO2 HAS TO BE DECLARED the instigator of the PRESENT warming of the atmosphere. Notably, this warming is going to affect the northern hemisphere more than the southern. This does not mean that we should be complacent because we live in Australia. We have already experienced some warmer dry bubbles in the centre of the continent that indicate the influence of global warming. A few years ago, an extra scale of temperature had to be added above the recorded 49 + degrees Celsius. 
Other factors such as methane are contributing to this warming, while the ice melt is only giving us a false sense of "not warming as much"... This is the ice in the whisky syndrome, slowly warming to room temperature. So. What are we going to do about it? Should we worry about it? 
Of course, we should do all we can AND MORE to reduce our emissions of CO2 to ZERO.
2018, as predicted by Gus on this site in previous comments, was not going to be "our warmest". Yet it still will be the fourth warmest year on record according to the experts. According to Gus, 2019 and 2021 are going to be scorchers under El Nino, as the sun wakes up from its quiet cycle in 2020, should no major volcanic eruption happen and should we have not gone to a full world war about the price of fish, which, in this latter case, would increase the warming several fold. This would be silly.
Global warming nonetheless is going to be worse than we can imagine. ANTHROPOGENIC CO2  is the culprit. We are responsible for it. We should fix it, but not with silly "engineering" using particles... This would upset the problem and make it more "unpredictable". The only solution — and WE HAVE TO BITE THE BULLET — is to reduce our emissions of CO2 to zero immediately. There is already enough anthropogenic CO2 to make our life a misery, soon.

Gus Leonisky
Your local cool zombie...